JPH01302358A - Image forming apparatus - Google Patents

Abstract

PURPOSE: To improve production speed and resolution by dissolving or molecularly dispersing charge transfer molecules into an electric insulating flexible layer and a charge transfer spacing layer. CONSTITUTION: Charge injection from an electrically photosensitive migration marking material 58 to an electric insulating softening layer 56 is increased by charge transfer molecules contained in the layer 56 and charge is transferred to a base body 52 and dissolved or molecularly dispersed into the layer 56. Namely, charge transfer molecules in a charge transfer layer 54 transfer charge carriers injected from an image forming layer to the base body 52 and dissolve or molecularly disperse the carriers into an electric insulating film forming binder layer. Thereby the image forming member can be used as an electrostatic printing master precursor member having an effective photosensitive characteristic. Consequently, prints of high quality and high resolution can be produced at a high production speed, and an image forming system suitable for both of color proofing and color printing/copying purposes can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Kokai ■ Background This invention relates generally to imaging apparatus, and more particularly, to improved migration-imaging members and electrostatic printing reproduction using the improved migration-imaging members. Regarding the law.

In printing/copying technology, various techniques have been developed to create masters for use in subsequent printing steps.

Lithography or offset printing is a well-known and established printing method. In general, the IJ) graph is a method of printing from a printing plate that relies on different inking characteristics in the printability of imaged and non-imaged areas. In conventional lithography, a lithographic intermediate is first prepared from an original image on a silver halide film; the printing plate is then exposed to intense UV light through the intermediate. The U■ exposure tip makes the exposed 0■ area of the printing plate hydrophilic or ink-receptive; the unexposed area is washed away by chemical treatment to make it hydrophobic or ink-repellent. Printing ink is then applied to a printing plate and the ink image is transferred to an offset roll where the actual printing takes place.

Although lithographic printing provides high quality prints and high printing speeds, this method requires the use of expensive intermediate films and printing plates. Additionally, they are significantly costly and time-consuming to fabricate, often requiring hot wire workers and strict process control standards.

A further disadvantage is the difficulty in setting up printing presses to obtain the proper water to ink balance necessary to obtain the desired results during the printing process. This results in further cost increases and time delays in obtaining a first acceptable print.

The above problems are particularly acute in the production of high quality color prints when several color separation images are overlapped on the same receiving medium. Due to the high cost and complexity associated with the production of expensive printing plates and press operations, color proofing is used to form preliminary prints (so-called proofs) from color separation components that allow the user to print the final print. It allows you to decide whether you are accurately reproducing the desired results. Separate components often require repeated replacement to satisfy the user. When the user is satisfied with the results, printing plates with each color separation component are prepared and finally used in a press operation. 0 examples of color proofing equipment are 1972E,
1. Cromarin (CI?) introduced by DuPont
OM/ILIN) and is widely used in the printing industry. The device consists of a photosensitive adhesive photopolymer layer laminated to paper. The photopolymer layer is contact exposed under a UV source through the color separation components. The exposed areas polymerize and lose their tackiness, while the unexposed areas remain tacky. A toner is then applied to adhere to the sticky areas. Because of the very different methods used in base proofing compared to press operations, the proof can at best simulate a press sheet. moreover,
Preparing color proofs is a time consuming process (eg, about 30 minutes for chromin proofs).

Electrostatographic printing is another well known printing method. In conventional electrostatographic printing, an electrostatic latent image is created by lens-achieved exposure to visible light or by laser scanning.
The electrostatic image is first formed on a conventional photoreceptor; toner is applied to the electrostatic image; and the toner image is then transferred to a receiving member.

Although this method offers the advantages of low skill and labor costs, ease of operation, and print stability, it is easy to simultaneously meet the requirements of high quality and high print speed in commercial printing at an acceptable cost. can't be satisfied. Because in order to give high quality and avoid certain artifacts, extremely high image-constituent molecular density (pict
This is because the ure-element density) is also required. If a new image is written on the photoreceptor with each print, for example, the conditions for high speed and high image-constituent molecule density depend on the electronic bandwidth and modulation speed and polygon rotation speed (when using laser scanning). It is unlikely that these will be available at reasonable cost in the foreseeable future. There is also no technology that directly overcomes this problem. Another problem associated with conventional electrostatographic printing is the need to repeat imagewise exposures continuously at high speeds.

Electrostatic printing is another electrostatographic printing method.

Conceptually, electrostatic printing overcomes the above problems in a very simple way. Electrostatic printing is an electrostatic printing process in which multiple copies are printed from a master plate or cylinder. A master plate is a metal sheet that has an imprinted image in the form of a thin electrically insulating coating. Master plates can be produced by photonic or electrostatographic methods. From the original image, a single electrostatic printing "master" is produced, e.g.
It can be made slowly in seconds. The imaging material is typically an electrical conductor with an imaged pattern of insulating areas produced by photonics or electrostatography; it has different charge acceptance in the imaged and non-imaged areas. . That is, - within the shell, the imaging surface of the master plate includes an electrically insulating image corresponding to the desired image shape and an electrically conductive area corresponding to the background; The electrostatic printing master is then uniformly charged; the charge remains trapped only in the insulating areas, toning the electrostatic image. After the toner is transferred to the paper and cleaned as necessary, the steps of charging, toner application, transfer and cleaning are repeated at high speed. In principle,
It is possible to retain much of the simplicity, stability and quality of electrostatography without repeated imagewise exposures. An additional advantage is that since the same area is toned repeatedly, there is no need to use a cleaning step. Moreover, conventional toners can be used to avoid the lack of color penetration problems encountered with comparable magnetic recording methods. The high contrast potential and high resolution of electrostatic latent images are important features that determine the print quality of documents produced by electrostatic printing. However, these prior art electrostatic printing methods have been found to produce poor prints. This is because an insulating image on a metal conductor cannot be sufficiently and uniformly charged near its environment. As a contrast potential builds up along the boundaries of the insulating image, the fringe electric field from the insulating image region repels acquired ions from the charge device (usually a corona charge device) into the adjacent conductive background region. This results in poor print quality as well as low contrast potential. Additionally, some electrostatic printing methods have a master and/or
or require many processing steps and complex equipment to produce the final electrostatic printed product. Also, some electrostatic printing methods require tedious photochemical treatment and removal of material in the imaged or non-imaged areas of the master.

U.S. Patent No. 3.574,6 granted to L. Carrilla.
In No. 14, an electrostatic printing master is placed between a blocking electrode and an injection electrode (one of which is transparent) in a photoelectrophoretic image-forming suspension (this suspension is an insulating carrier). (containing a plurality of photoelectrophoretic particles in a liquid) and imagewise exposing said suspension to electromagnetic radiation through transparent electrodes to form a complementary image on the surface of each electrode. (the exposed particles migrate from the injection electrode to the blocking electrode), one of the images is transferred to a conductive substrate, and an organic insulating binder is uniformly applied to this image-bearing substrate to form the image and non-image. The binder thickness in the double head area of the formation is 1-2
An electrostatic printing method is disclosed which consists in providing a thickness in the range of 0 μm. This electrostatic printing method applies a uniform charge to the surface of an image-bearing substrate in the presence of electromagnetic radiation to form an electrostatic residual charge image corresponding to the non-imaging areas (areas free of photoelectrophoretic particles). , developing the residual charge image, transferring developer from the residual charge image to a copy sheet, and repeating the charging, developing and transferring steps described above.

Alternatively, the insulating binder may be intimately mixed with the dispersion of photoelectrophoretic particles before inserting the liquid mixture between the electrodes. The region into which the photoelectrophoretic particles migrate becomes insulating and capable of supporting electrostatic charges. A major problem is that an insulating image supported directly on a conductive substrate cannot be charged near its periphery because the fringe electric field directs the acquired ions to the grounded substrate. Another drawback of such methods is that they require the preparation of the master using a liquid photoelectrophoretic imaging suspension. Furthermore, the master fabrication method is extremely complex and involves the removal of one of the electrodes, the transfer of a complementary image to one conductive substrate, and the application of an organic insulating binder to the conductive substrate. Such a complicated master production method is disadvantageous to the user and can adversely affect print quality. It also requires additional time to dry the image before use as an electrostatic printing master.

Unlike the liquid photoelectrophoretic imaging suspension systems described in U.S. Pat. No. 3,574,614, solid imaging members have been developed for dry migration systems.

Dry migration imaging members are described in the patent literature, for example, U.S. Pat.
No. 09.262 and U.S. Pat. In typical embodiments of these migration imaging systems, a migration imaging member comprising a substrate, a layer of softenable material, and a photosensitive marking material is first charged and the charged member is exposed to light. The photosensitive marking material is essentially continuous with the top surface of the softenable layer. When the material is in the form of a destructible layer, the Mar-Tong particles in the exposed areas of the member migrate deeper towards the substrate when the member is developed by softening the softenable layer.

As used herein, the expression "softenable" shall mean any material that can be made more permeable, thereby allowing particles to migrate through its bulk. Changes in the permeability of the material such as -υ or ma, igu/- may reduce the resistance to migration of the marking material, e.g. by heat, water degassing, partial solvent, ) melting, swelling, by methods such as contact with medium vapor, refrigerants and combinations thereof;
This is done by melting or softening, or by reducing the viscosity of the softenable material by any suitable means.

As used herein, the term "destructible" layer or material refers to any layer or material that can be destroyed during development, thereby causing a portion of this layer to transfer to the substrate or otherwise be removed. This rupturable layer is preferably granular in various embodiments of the migration imaging member. Such a rupturable layer of marking particles typically consists of a softened layer separated from the substrate. The destructible layer is continuous with the surface of the softenable layer, and such a destructible layer may be incorporated substantially or entirely into the softenable layer in various embodiments of the imaging member.

As used herein, the term "continuous" refers to actual contact; light contact: contact ξ;
close to, but not close to,; and adjacent shall mean inclusively describing the relationship of the marking material in the softenable layer to the convertible layer surface remote from the substrate of the breakable layer; shall be.

As used herein, “optically code-preserving”
The term ``clear (high optical density) and bright (low optical density) areas of the visible image formed on the migration imaging member correspond to the dark and bright areas of the image on the original paper used. It is assumed that it is appropriate for the area.

As used herein, “optical G sign inversion”
”
The expression is that the dark areas formed on the migration imaging member L correspond to the bright areas of the image on the original paper, and the bright areas formed on the migration imaging member correspond to the bright areas of the image on the original paper used. Let If' mean correspond to a region.

As used herein, the expression “optical contrast density” refers to the highest optical density (D, , ) and the lowest optical density (D, i
n). Optical density, for purposes of the present invention, is defined as blue
No. Measured with a diffusion densitometer with a 94 filter. As used herein, the expression “optical density” means “
"transmitted optical density", which is expressed by the following formula: %, where l is the transmitted light intensity and 10 is the irradiated light intensity. All values of transmission optical density used herein encompass substrate densities of about 0.2, which is a typical density for metallized polyester substrates.

Other such imaging systems comprising non-photosensitive or inert marking particles arranged in the breakable layer or dispersed in the softenable layer described above are also described in the above-mentioned U.S. patents. These US patents also disclose various methods that can be used to form latent images on migration imaging members.

A variety of latent image development means can be used in migration imaging systems. These development methods include solvent washing removal method,
Solvent vapor softening methods, thermal softening methods, and combinations of these methods, as well as imagewise migration of deep particles toward the substrate by altering the resistance of the softenable material to migration of particulate marking particles through the softenable layer. There are any other methods that allow.

In the negative (minus) development method including the solvent washing removal method,
The migration marking particles in the light irradiated area are softened and transferred to the substrate through the dissolved softening layer, and are refilled in the shape of a monomolecular layer. In a migration imageable film supported only by a transparent substrate, this region exhibits a high maximum optical density similar to the initial optical density of the untreated film. On the other hand, the migration marking particles in the unexposed area are substantially washed away and this area exhibits a minimum optical density that is essentially the optical intensity of the substrate alone. Therefore, the development sensitivity is optically reversed in sign, that is, positive vs. negative or vice versa. Various methods, materials and combinations thereof have previously been used to fix such unfixed migration images.

In heated or steam softening development methods, migration marking particles in the exposed area migrate deep into the softenable layer after development, and this area typically has a D + at n in the range of 0.6 to 0.7. shows. This relatively high Dl,
7 is a direct result of the deep dispersion of the other unchanged migration marking material. - On the other hand, the migration marking particles in the unexposed area do not migrate and remain in their original shape.
That is, it substantially remains in the monomolecular layer. In a migration imageable film supported on a transparent substrate,
This region exhibits the highest optical density of about 1.8-1.9. Therefore, the sensitivity of heated or steam-developed images is sign-retaining, that is, positive vs. negative is negative vs. negative.

Although techniques have been devised for optically sign-reversing imaging by vapor development, these techniques are generally complex and require critically tailored process conditions.9 Such techniques, for example, Described in US Pat. No. 3,795,512.

In many imaging applications, it is preferable to form a positive image from a positive original image or a positive image from a negative original image, ie, to form an optically sign-reversed image with a low minimum optical density. Although negative or solvent wash removal development methods form optically sign-reversed images at low minimum optical densities, these methods involve removal of material from the migration imaging member and are largely or totally protected from abrasion. The unused imaging member remains. Although various methods and materials have been used in the past to overcoat such unfused migration images, overcoating after development is impractical and costly and disadvantageous to the user. More importantly, during development, the disposal of wash effluent from the migration imaging member can be extremely expensive.

Although heat or vapor development methods are preferred because they are rapid, essentially dry, and produce no liquid effluent, the texture of heat or vapor developed images is optically code-retaining and has a very high minimum optical density.

Background portions of the imaging member can sometimes be made transparent by agglomeration and fusion effects. In this system, an imaging member that includes a softenable layer that includes a destructible layer of electrically photosensitive migration marking material is prepared in one method embodiment by electrostatically charging the member at 8. Migration material in the softenable layer in areas previously exposed to the activating radiation by exposure to an image-forming pattern of activating electromagnetic radiation and softening by exposing the softenable layer to solvent vapor for a few seconds. The image is formed by causing selective migration in the deep part of the body. The steam developed image is then subjected to a heating step. Because the exposed particles acquire a substantial net charge (typically 85-90% attached surface charge) as a result of light exposure, the exposed particles become soft towards the substrate when exposed to solvent vapor. It migrates substantially deeper into the layer, thus resulting in a dramatic decrease in optical density. The optical density in this region is typically in the range 0.7-0.9 after exposure to steam compared to an initial value of 1.8-1.9. In the unexposed areas, the surface charge is discharged by vapor exposure. The subsequent heating step causes the untransferred, uncharged migration material in the unexposed areas to agglomerate, often with coalescence of the marging material particles, thereby causing 0.25-0.
It gives a very low minimum optical density migration image (in the unexposed areas) in the 35 range. That is, the contrast density of the final image typically ranges from 0.35 to 0.65. A migration image can also be formed by heating, then exposing to solvent vapor, and then subjecting to a second heating step; this method also provides a migration image having an optical density with an extremely low minimum optical density. In this image forming method and the heating or steam development method described above,
The softenable layer remains substantially intact after development and the image is self-fixing as the marking material particles are entrapped within the softenable layer.

Although the minimum optical density of the image using such a method is considerably reduced - statically, the maximum optical density (D, , )
There is a simultaneous dramatic drop in
As a result, the contrast density (D, , -D,i,) is also low.

The term "agglomeration" as used herein is defined as the aggregation and attachment of previously substantially separate particles without loss of particle individuality.

The term "fusion" as used herein is defined as the fusion of such particles into larger units, usually accompanied by a change in the shape of the aggregates to a lower energy shape, such as a spherical shape.

-m, the softenable layer of the migration imaging member is particularly sensitive to abrasion and external contamination.
h is attached. Because the destructible layer is present at or near the surface of the softenable layer, due to abrasion, some of the destructible layer can be easily removed during manufacture or use of the film without adversely affecting the final image.

External contamination such as fingerprints can also cause defects to appear in the final image. Furthermore, softenable layers tend to cause blocking of the migration imaging member when stacking the members or when the migration imaging material is rolled for storage or transportation. Blocking usually results in deterioration of the object when separated.

Sensitivity to wear and external contamination is U.S. Patent No. 3,9
It may be reduced by forming an overcoating such as that disclosed in US Pat. No. 09,262. However, the migration image formation mechanism in each development method is different, and these mechanisms depend on the electrical properties of the surface of the softening layer, charge injection from the surface, charge transport through the softening layer, charge capture by photosensitive particles, and The application of overcoats to softenable layers often involves a delicate balance of the above processes, as it is critically dependent on the complex interplay of various electrical processes, including charge release from the photosensitive particles, etc. changes in the properties of the migration imaging member without overcoating and a reduction in photographic properties compared to migration imaging members without overcoating. Significantly, the photographic contrast density is reduced.

Recently, improvements have been made in migration imaging members and methods of imaging on these migration imaging members. These improved migration imaging members and methods are disclosed in U.S. Pat. No. 4,536.458 to Dominic S., Ng and U.S. Pat. ．． 157
It is stated in the number.

U.S. Pat. No. 3,574,614, issued April 3, 1971 and issued to Carreira, discloses the use of a layer of photoelectrophoretic imageable suspension between a blocking electrode and an injection electrode. When subjected to an applied electric field (one of the electrodes is transparent and the suspension contains a plurality of photoelectrophoretic particles in an insulating carrier liquid), the suspension is electromagnetically transferred through a transparent electric bridge. The lines are imagewise exposed to form a complementary image on each electrode surface mound (
(the exposed particles migrate from the injection electrode to the blocking electrode), one of the images is transferred to a conductive substrate, and an organic insulating binder is uniformly applied to this image-bearing substrate to form both imaged and non-imaged surfaces. Binder thickness within the area is 1 to 20 μm
applying a uniform charge to the surface of the image-bearing substrate in the presence of electromagnetic radiation to form an electrostatic residual charge image corresponding to the non-imaged areas (areas without photoelectrophoretic particles);
A method is disclosed comprising developing the residual charge image, transferring developer from the residual charge image to a copy sheet, and repeating the charging, developing and transferring steps described above. Alternatively, the insulating binder may be intimately mixed with the dispersion of photoelectrophoretic particles prior to inserting the liquid mixture between the electrodes. The region into which the photoelectrophoretic particles migrate becomes insulating and capable of supporting electrostatic charges.

U.S. Pat. No. 4,536.457, issued Aug. 20, 1985, to M. C. Tam, includes a substrate and an electrically insulating softenable layer on the substrate, the softenable layer being attached to the substrate. a migration marking material and a charge transport molecule present at least at or near the surface of the softenable layer remote from the imaging member (e.g., the imaging described in U.S. Pat. No. 4,536,458). Discloses a method for uniformly charging and imagewise exposing a member to activating radiation. The resistance to migration of the marking material in the softenable layer is then sufficiently reduced by application of a solvent vapor to effect a slight migration of the marking material deep towards the substrate in an imagewise manner;
The resistance to migration of the marking material in the softenable layer is reduced sufficiently by heating to cause the unexposed marking material to agglomerate and fuse. The preferred thickness is about 0.5~
2.5 μm, but thicker or thinner layers can also be used.

U.S. Pat. No. 4,536,458, issued Aug. 20, 1985, to Dominic S., N.G., includes a substrate and an electrically insulative softenable layer on the substrate, the softenable layer extending from the substrate. Migration imaging members are disclosed that include migration marking particles and charge transport molecules present at least at or near the surface of the softenable layer that are spaced apart. The migration imaging member is electrostatically charged and imagewise exposed to activating radiation to render it resistant to migration of marking material deep within the softenable layer, at least to enable migration of marking particles. The marking material is developed by exposure to solvent vapor or reduction by heating sufficient to cause the marking material to migrate in image form towards the substrate. The preferred thickness of the softenable layer is about 0.7 to 2.5 micrometers, although thicker or thinner layers can be used.

U.S. Pat. No. 2,576.047, issued Nov. 20, 1951, to R. Scha Novert, describes, for example, electrostatically charging an image-shaped insulating pattern coated on a metal drum. discloses an electrostatic printing apparatus and method comprising subsequent development with a developer powder. The resulting powder image on the insulating pattern is electrostatically transferred to the receiving member.

The insulating pattern is cleaned and reused.

U.S. Pat. No. 3,967.818, issued July 6, 1976, to R. Gandrasohi, discloses a reproduction apparatus for a school copy set of collated information. The electrostatic printing master can be used as a master scroll that can also move in reverse directions. This master is electrostatically charged, developed, and the resulting toner image is transferred to a receiving member.

U.S. Pat. No. 3,765,330, issued to R. Gundlach on October 16, 1973, discloses a conductive substrate having a concave and convex surface of the same material that contacts the relief surface but straddles the concave surface without contacting it. A uniform charge is applied to the printing master to form a discharge area in which the resistive material is in contact with the relief surface. The resistive material forms a charged area spanning the concave surface.The printing master is then developed to electrostatically transfer the developed image to the transfer sheet.

US Pat. No. 4,407,918, issued October 4, 1983 to E. 5ato, discloses an electrophotographic method and apparatus for making multiple copies from a single image. an electrically conductive substrate, a first photoconductive layer applied on the substrate, a charge retentive insulating layer applied on the first photoconductive layer, and a second photoconductive layer applied on the charge retentive layer. A photosensitive member is described that includes an electrically conductive layer. This photosensitive member is uniformly charged to a negative polarity and exposed to visible light. An image of the original to be copied is projected, while the photosensitive member is positively charged. The photosensitive member is then exposed to visible and ultraviolet light, thereby capturing a charged latent image in the charge retentive layer.

US Pat. No. 4,518,668, issued May 21, 1985 to Nakayama, discloses a method for making lithographic printing plates. A photosensitive material comprising a photosensitive layer and a photoconductive insulating layer is imagewise exposed and processed to form an electrostatic latent image on the photoconductive insulating layer. The image is then developed with charged opaque developer particles. This development is used for contact exposure of the underlying photosensitive lithographic master layer.

U.S. Pat. No. 4,520,089, issued May 28, 1985 to Tattoo et al., discloses an electrophotographic offset comprising a base paper and a backing coating layer made of Sericy 1 on one side thereof. Master is disclosed.

The other side of the base paper has a precoated layer of photoconductor and an adhesive. This master is used for imagewise exposure of the photoconductor,
It is produced by subsequent development and fixing.

U.S. Pat. No. 4,533,611, issued Aug. 6, 1985 to Winkleman, discloses a lithographic process comprising forming and removing a charged image on a photoconductive layer and an insulating film-L thereon. A method of making a printing plate is disclosed.

The image was then developed and transferred to a printing plate.

There are many drawbacks to these prior art methods. For example, certain prior art electrostatic printing methods provide poor image quality due to their poor resolution capabilities caused by fringe electric fields as discussed above. Some electrostatic printing methods require a master and/or
or require numerous processing steps and complex equipment to produce the final electrostatic printed product. Some electrostatic printing methods also require tedious photochemical treatment and removal of material in imaged or non-imaged areas of the master. In some attempts, the insulating image is replaced by an "I leaky" insulator, that is, one that accepts and retains charge for a longer time than the time it takes to apply the charge to each particular spot, but does not charge the latent image. It is formed on a substrate that discharges with a relaxation time shorter than the time during image development.

The basic problem with this approach is that most resistive (current leakage) insulating films are sensitive to relative humidity and, in some cases, to age and temperature as well. In other words: Relaxation times vary beyond acceptable limits over normally encountered ranges of relative humidity, temperature, and product life. Color printing that requires /
It is particularly critical in copying applications.

Accordingly, there is a need for improved imaging members and improved electrostatic printing methods.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved image suitable for both color proofing and color printing/copying applications, having the combined advantage of producing high quality, high resolution prints at high production speeds. The objective is to provide a formation system.

These and other objects of the present invention provide that a substrate, a conductive layer, an intermediate layer comprising an adhesive layer, a charge transport spacing layer comprising an electrically insulating film-forming binder, or said adhesive layer and said charge transport spacing layer. (10) an imaging layer comprising an electrically insulating softenable layer of charge transport spacing layer 1o; a destructible layer of closely spaced particles of electrically photosensitive migration marking material present at or near the substantially imaging surface of the layer; It is possible to increase the charge injection from the electrically photosensitive migration mer-tongue material r1 to the insulating softenable layer, and the charge can be transferred to the substrate, and the charge can be dissolved or molecularly dispersed in the electrically insulating softenable layer. charge transport molecules in the charge transport layer are capable of transporting charge carriers injected from the imaging layer to the substrate and are dissolved or molecularly dispersed in the electrically insulating film-forming binder layer; This is accomplished by providing an improved imaging member featuring the following characteristics: This improved imaging member can be used as a master precursor member for electrostatic printing, exhibiting good photosensitivity properties.

The imaged members of the present invention include a substrate and an electrically insulating softenable layer on the substrate, the softenable layer carrying charge transport molecules and substantially the surface or surface of the softenable layer remote from the substrate. a destructible layer of an electrically photosensitive migration marking material in close proximity, the softenable layer having a thickness of about 3 to about 30 μm, preferably about 4 to about 25 μm, and wherein the charge transport molecules are capable of increasing charge injection into the softenable layer from the electrically photosensitive migration marking particles, capable of transferring charge to the substrate, and dissolved or molecularly dispersed in the softenable layer; providing a migration imaging member characterized by; electrostatically charging the member to deposit a uniform charge on the member;
The member is imagewise exposed to activating radiation before the uniform charge substantially decays, whereby the electrically sensitive migration marking material exposed to the activating radiation acquires charge carriers. Excite with light;
The resistance to migration of the migration marking material in the softenable layer is sufficiently reduced to create a negligible net charge on the exposed migration marking material.
arge) and this net charge further reduces the resistance to migration of the marking material in the softenable layer, while at most there is a slight increase in the image shape in the depths of the marking material towards the substrate. furthermore, the resistance to migration of the marking material in the softenable layer is sufficiently reduced to permit unexposed marking material to It is produced by substantially aggregating and fusing.

The imaged members of the present invention include an electrically insulating softenable layer having a substrate and an imaging surface overlying the substrate; a destructible layer of closely spaced electrically photosensitive migration marking particles in an imaged pattern substantially at or near the imaging surface of the electrically insulating layer; the imaging pattern is substantially absorptive and opaque to activating radiation in a spectral region in which the migration marking particles photoexcite charge carriers, and is electrostatically charged and exposed to activating electromagnetic radiation; , in at least one other region of said electrically insulating layer, electrically photosensitive migration marking particles substantially present within said electrically insulating layer; When aggregated and fused into a pattern adjacent to or complementary to an image-forming pattern of migration marking particles, exhibits a substantial photodischarge; the size of the aggregated and fused electrically photosensitive migration marking particles the size is substantially greater than the size of the adjacent image-forming pattern of closely spaced electrically photosensitive migration marking particles, and the number of agglomerated and fused electrically photosensitive migration marking particles is substantially greater than the size of the adjacent image forming pattern of closely spaced electrically photosensitive migration marking particles; The pattern of agglomerated and fused electrically photosensitive migration marking particles is smaller than the number of formation patterns; the migration marking particles have substantially less absorption to electromagnetic radiation for activation of spectrum particles that photoexcite charge carriers. and exhibits a substantially smaller photodischarge compared to the photodischarge of the adjacent imaging pattern of said closely spaced electrically photosensitive migration marking particles; Charge injection into the electrically insulating layer from marking particles can be increased, charge can be transferred to the substrate, and are dissolved or molecularly dispersed in the softenable layer and charge transport spacing layer.

The imaged member deposits a uniform electrostatic charge over the entire imaging surface of the electrostatic printing master; electrically photosensitive migration marking particles uniformly exposed to light to substantially discharge and aggregate and coalesce the imaging surface covering said imaged pattern of closely spaced electrically photosensitive migration marking particles; forming an electrostatic latent image on the imaging surface area overlying the complementary pattern of the layer; developing the imaging surface with electrostatically adherent toner particles to form a toner image corresponding to the imaging pattern of the complementary pattern; It can be used as an electrostatic printing master in an imaging process that involves forming and transferring a toner image to a receiver member.

BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention and its features more clearly, the invention will now be described in more detail with reference to the drawings showing various preferred embodiments.

Typical electrostatic printing masters suitable for use in the electrostatic printing process described above are shown in FIGS. 1, 2, and 3. 1st
In the figure, a substrate I2 with an optional conductive layer 4; an optional charge transport spacing layer 1 comprising a film-forming polymer and a charge transport molecule;
6, and a softening layer 18 coated on the second
An electrostatic printing master precursor member 10 is illustrated, wherein the softenable layer 18 includes a charge transport material and a destructible layer of migration marking material 20 continuous with the top surface of the softenable layer 18. The particles of marking particles 20 appear to be in contact with each other in the drawing due to the physical limitations of such a schematic illustration. However, the particles of marking material 20 are actually separated from each other by less than a micron. In various embodiments, support substrate 12 can be either electrically insulating or electrically conductive. For example, the support substrate 12 can be an electrically conductive metal drum or plate. In some embodiments, the electrically conductive substrate may include a supporting substrate 12, such as an aluminized polyester film, having a conductive coating 14 on its surface, on which an optional charge transport spacing layer I6 or Coat the softenable layer 18.

Substrate 12 may be opaque, translucent, or transparent in various embodiments, including embodiments in which conductive layer 14 coated thereon is itself partially or substantially transparent. A destructible layer of marking material 20 that is continuous with the upper surface of softenable layer 18 is slightly, partially, substantially or completely embedded in the softenable layer at the upper surface of softenable layer 18 . There is.

In FIG. 2, a supporting substrate 12 is shown as an electrostatic printing master having a conductive coating 14, an optional adhesive layer 22, an optional charge transport layer 16, and a softenable layer 18 coated thereon. Another multilayer overcoating embodiment of the precursor member is illustrated. Migration master material 20
are initially arranged in a rupturable layer that is continuous with the upper surface of the softenable layer 18.

In the embodiment of FIG. 3, the electrostatic printing master precursor component simply includes a supporting substrate 12, a conductive layer 14, and a coating convertible layer 18. The migration marking material 20 is initially arranged in a rupturable layer that is continuous with the upper surface of the softenable layer.

Although not illustrated, the embodiments shown in FIGS. 1.2 and 3 may also include an optional overcoating layer coated over the softenable layer 18.

In various embodiments of the novel electrostatic printing masters of the present invention, the overcoating layer may include a non-adhesive or release material, or the outer layer may include multiple layers including a non-adhesive or release material.

The electrostatic printing master precursor parts shown in Figures 1.2 and 3 differ significantly from conventional electrostatic printing master precursor parts in the way they are constructed, made and used. For example, typical prior art electrostatic printing masters are often prepared by a prioritizing removal of material from unexposed areas. In FIG. 4, the imaging master 24 is a conductor 26 having an imaging pattern of insulating material 28, typically made by electrophotography or electrostatography. The master has different charge acceptance in the insulating imaging areas 30 and the conductive non-imaging areas 32.

The electrostatic printing master 24 is then charged by a suitable device, such as a corotron 34, as shown in FIG. The geometric boundary between the insulating image area and the conductive background area creates a strong fringe electric field as charges accumulate on the insulating image surface, further deflecting ions into the conductive background and preventing high charge density against the boundary W. ing. This gives blurred low-density fine lines as well as indistinct low-density edges of large solid areas. The deposited charge remains trapped only on the imaged pattern of insulating material 28. In the case of some prior art,
The non-imaged areas were covered with a resistive film with a charge relaxation time constant longer than the corona charging time but shorter than the time between charging and development. The difficulty in this attempt is that the tolerances are small and the relaxation time constant changes from batch to batch.
or in the range of relative humidity normally encountered, or even over time. This electrostatic image is then created by delivering toner particles charged to a polarity opposite to that of the charge on the imaged pattern of insulating material 28, thereby creating a deposited toner image 38 as shown in FIG. Toner can be applied by conventional electrostatographic development methods to form 40.

In FIG. 7, the deposited toner images 38 and 40 are transferred from the imaged master 24 to a suitable receiving sheet 42, e.g. Transfer by applying a uniform charge. Following transfer of the toner image to receiver sheet 42, the transferred toner image may be fixed by known methods such as fusing, laminating, or the like. The upper surface of electrical conductor 26 and the imaged pattern of insulating material 28 are then
It may be cleaned if necessary. The charging, toner application, transfer and cleaning processes are repeated at high speed. In principle, it is possible to retain much of the simplicity, stability and quality of electrostatography without repeated image exposures. An additional benefit is that the same surface can be toned repeatedly.
There is no need to use a cleaning process. Moreover, using conventional toners, the lack of color penetration encountered in comparable methods using, for example, magnetic recording methods can be avoided.

Despite the conceptual simplicity of electrostatic printing, it is actually a classic problem in electrophotographic technology. Despite much of the early efforts and documentation of electrostatography,
There continues to be a challenge to develop methods of producing high quality prints. The problem with this electrostatographic master is that the insulator must have a reasonable thickness and the voltage on the electrostatic master must be high enough for good electrostatographic development. As shown in FIG. 8, when the electrostatic printing master 44 is charged, a fringe electric field (not shown)
occurs between the conductor 46 and the imaged pattern of insulating material 48. These fringe fields tend to extend over significant distances and deflect additional acquired ions 46. The non-uniform charge of the resulting imaged pattern of insulating material 48 severely limits the resolution of the final print, defeating the purpose of electrostatic printing for high quality purposes. Although the resolution can be improved by special methods, it is too critical for practical use.

The manufacturing process of the improved electrostatic printing master of the present invention is shown in FIGS. 9 to 12. In connection with FIG. 9, an electrically grounded conductive substrate 52, a charge transport Ji 54, a softenable layer 5
6 and a destructible layer of migration marking material 58 , the electrostatic printing master precursor member 50 is uniformly positively charged by a corona charging device 60 . A uniformly charged master precursor member 50 for electrostatic printing,
Thereafter, as shown in FIG. 1θ, it is exposed to activating radiation 62. Next, the exposed master precursor member 50 for electrostatic printing is exposed to solvent vapor 6 as shown in FIG.
Expose to 4.

With reference to FIG. 12, application of thermal energy 66 to the solvent treated electrostatic printing master precursor member completes the conversion of the precursor member to an electrostatic printing master 72. In the exposed areas of the destructible layer of migration marking material 68, the exposed particles acquire a small net charge as they are scratched, which causes only slight agglomeration, fusion or a combination of agglomeration and fusion of the exposed migration marking material upon subsequent heating. produced in a process, and/or
At most, it allows only a slight migration in the depths of the migration marking material towards the substrate. This is the glue inside the wound, the □ area.

For illustrative purposes, the depiction in FIG. 12 of agglomeration and/or slight migration is an exaggeration. 8. The unexposed particles substantially aggregate and coalesce to form relatively small but large agglomerates or spheres 70; Give area.

That is, the development in the final electrostatic printing master 72 is an optically sign-reversed image of the original image (when using a conventional optical lens exposure system), giving an extremely low background density D min .

The electrostatic printing master 72 produced above can then be used in an electrostatic printing process. The use of an electrostatic printing master in an electrostatic printing process is shown in FIGS. 13-17. The softening layer 56 of the electrostatic printing master 72 is shown in FIGS.
The figures are enlarged to facilitate explanation of this electrostatic printing method. In FIG. 13, an electrostatic printing master 72 is uniformly and positively charged by a corona charging device 74. In FIG. However, unlike most of the earlier attempts shown in FIG. is nothing. The charged electrostatic printing master 72 is then uniformly flash exposed to light energy 76 as shown in FIG. - As mentioned above, there is a difference in light absorption properties based on the difference in the relative size and number of migration marking materials in the D, □ area and the D n i n area (i.e., D
The uniform exposure to light energy is D
@ @ causing the imaging surface portion of the softenable layer on the An electrostatic latent image is formed on the electrostatic printing master as shown in the figure. In other words, the D m i 6 j JI region (agglomerated and fused electrically sensitive migration marking particles) of the electrostatic printing master of the present invention exhibits relatively poor or "contaminated" photoreceptor characteristics. The D and □X regions exhibit relatively good photoreceptor characteristics.

The terms "poor" and "good" are used herein to mean that the background potential is at least 30%, preferably at least 40%, of the initial common surface potential at uniform charging and uniform exposure.
A good photoreceptor is one that exhibits a low background potential. That is, by uniformly charging the electrostatic printing master of the present invention and then uniformly irradiating it, discharge is produced primarily in the I)M, , l regions of the image. In FIG. 15, electrostatic latent image 78 is developed with toner particles 80 to form a toner image corresponding to the electrostatic latent image on area D min . In FIG. 15, toner particles 80 carry a negative electrostatic charge and are attached to oppositely charged portions on the 1.7 area (agglomerates or spheres 70). However, if desired, toner may be applied to the discharged areas using toner particles having the same polarity as the charged areas (positive in the embodiment shown in FIG. 15). At that time, the developer beam will be repelled by the charges on the area and will adhere to the discharge area (area D, 3). Well-known electrically biased development electrodes may also be optionally used to direct toner particles to either charged or discharged areas of the imaging surface. As shown in FIG. 16, the adhered toner image is transferred to a receiving member 82, such as paper, by applying an electrostatic charge to the backside of the receiving member by a corona device 84. The transferred image is then fused by conventional means (not shown), such as an open fuser. After transferring the toner image, the electrostatic printing master is
If desired, it can be cleaned to remove any residual toner that may be present and then erased by intense electromagnetic radiation 85 as shown in FIG. 17 or by an AC corotron. The development, transfer, fixing, cleaning and erasing steps are the same as those commonly used in electrostatographic image formation.

The supporting substrate can be either electrically insulating or electrically conductive. The substrate and the entire electrostatic printing master precursor member supported by the substrate can be made of a web, foil, laminate or the like, strip, sheet, coil, cylinder, drum, endless belt, endless Möbius strithop, disc or other It can be any suitable shape, including shapes. The present invention is particularly suited for use in either of these configurations. Typical supporting substrates include aluminized polyester, polyester films coated with transparent conductive polymers, metal plates, drums, and the like. In some embodiments, the electrically conductive substrate can include a supporting substrate, such as an aluminized polyester film, having a conductive layer or coating coated on the surface, on which also optionally Coating an adhesive layer, an optional charge transport spacing layer or a softenable layer. The substrate can be opaque, translucent, or transparent in various embodiments, including embodiments in which the conductive layer coated thereon is partially or substantially transparent. The conductive layer can be, for example, a thin coating of a vacuum evaporated metal or metal oxide, a metal foil, conductive particles dispersed in a binder, and the like. Typical metals or metal oxides include aluminum, indium, gold, tin oxide, indium tin oxide, silver, nickel, and the like.

Any suitable adhesive 4 can be used in the adhesive layer as an optional component of the present invention. Typical adhesive materials include the styrene and acrylate copolymer DuPont 49000.
(E, I, available from DuPont), acrylic copolymers of conitrile and vinylidene chloride, polyvinyl acetate, polyvinyl butyral, and mixtures thereof. When using an adhesive layer, approximately 0.5μ to ensure a satisfactory discharge during electrostatic printing
A uniform continuous film should be formed with a thickness of less than m. This adhesive may also contain charge transport molecules, if desired.

An optional charge transport spacing layer 16 may be used to transport injected charge from the imageable softenable layer to the conductive layer 1 and the conductive layer or substrate (where the substrate is electrically conductive and separate (in the absence of an adhesive layer); and increasing the spacing between the imaging surface and the conductive layer to increase the electrostatic contrast potential of the electrostatic latent image. perform important functions. By separating the film structure into various layers, the present invention allows for the selection of appropriate materials to optimize the mechanical, chemical, electrical, imaging and electrostatic printing properties of the imaging member. allows maximum flexibility.

The electrostatic contrast potential required for good quality prints depends on the particular type of developer used (eg, dry or liquid) and the development speed required for the particular application. −
Within the shell, contrast potentials in the range of 50 to 500 volts are suitable for liquid development systems, whereas contrast potentials in the range of 200 to 800 volts are required for dry toner development systems. It should be noted that the electrostatic contrast potential of the electrostatic latent images of the present invention is dependent on the total thickness of the imageable softenable layer and the optional charge transport spacing layer.

In dry development systems, the sum of j7 above is generally about 4
The thickness of the optional charge transport spacing layer ranges from about 2 to 25 μm. Somewhat thinner layers may be used if print density is sacrificed or slower development speeds are acceptable. Thicker layers than those described above can be used, but further increases in contrast potential do not provide further improvement in image quality, and the time required to remove solvent from each layer (during manufacturing or imaging) becomes impractical, making each layer The capture solvent within can cause blocking. Excellent results are achieved with a total thickness of about 5 to about 25 μm and an optional charge transport spacing layer thickness of 3 to 20 μm. In liquid development systems, the total thickness generally ranges from about 3 to about 25 microns, with the optional charge transport spacing layer thickness ranging from 1 to 20 microns. Excellent results are achieved with a total thickness of about 4 to about 20 μm and an optional charge transport spacing layer thickness in the range of 2 to 15 μm. For example, if an electrostatic contrast potential of about 200 volts of the latent image is desired, and assuming that the background potentials of the DIIIK and RI1.7 areas differ by about 50% of the initial applied surface potential, then the electrostatic The printing master needs to be charged to an initial surface potential of about 200 volts. If the electrostatic printing master is charged with an applied electric field of 100 v/μm, a total thickness of about 4 μm will satisfy both dry and liquid developer requirements.

Although both the softenable layer and the charge transport layer may contain a charge transport material to enable efficient charge transport, the primary role of the charge transport layer is to transport charge and function as a spacing layer, while The role of the softenable layer is both to transport charge and to ensure a proper charge injection process between the migration marking material and the softenable layer in the formation of a visible image. The softenable layer and the charge transport spacing layer may have the same or different binder materials and/or charge transport materials to improve the mechanical, chemical, and mechanical properties of the imaging member.
Electrical, image forming and electrostatic printing properties can be optimized. For example, some materials, such as styrene/hexyl methacrylate, exhibit excellent migration imaging properties but have insufficient flexibility (particularly when their thickness is 10
when increased by more than μm) and adhesive properties.

On the other hand, other materials, such as polycarbonate, exhibit good flexibility and adhesion but relatively poor migration imaging properties. That is, by including a separate charge transport spacing layer between the softenable layer and the substrate, for example, 2 μm thick styrene/hexyl methacrylate in the softenable layer and 5 μm thick polycarbonate in the charge transport spacing layer. can be used to optimize its imageability, electrostatic printability and mechanical properties.

Charge transport spacing layer 16 may include any suitable film-forming binder material. Typical film-forming binder materials include styrene acrylate copolymers, polycarbonates, copolycarbonates, polyesters, copolyesters, polyurethanes, polyvinyl acetate, polyvinyl butyral, polystyrene, alkyd-substituted polystyrenes, styrene-olefin copolymers,
Styrene-co-n-hexylmecrylate, custom synthesis with intrinsic viscosity 0.179 d//gm +30/
20 mole % styrene-hexyl methacrylate copolymers, other styrene-hexyl methacrylate copolymers, styrene-vinyltoluene copolymers, polyalphamethylstyrene, and mixtures or copolymers thereof. These groups of materials are not limiting and are merely illustrative of those suitable as film-forming binder materials for the optional charge transport spacing layer. These film-forming binder materials are typically electrically insulating and do not react adversely chemically during the production of the electrostatic printing master and the electrostatic printing process of the present invention. be. Although the optional charge transport spacing layer has been described as a coating on a substrate, in some embodiments the charge transport spacing layer itself has sufficient strength and integrity to be substantially self-contained. It may be supported and, if desired, contacted with a suitable conductive substrate during the imaging process. A uniform deposition of electrostatic charge of appropriate polarity may be substituted for the conductive layer, as is well known in the art.

Also, the uniform deposition of an electrostatic charge of appropriate polarity on the exposed surface of the charge transport spacing layer can be replaced by a conductive layer to facilitate the passage of electrophoretic forces to the migration layer. This "double charging" technique is well known in the art.

Charge transport molecules for the charge transport spacing layer are detailed below in the description of the softenable layer. The particular charge transport molecules used in the charge transport spacing layer of any resulting master may be the same or different from the charge transport molecules used in the adjacent softenable layer. Similarly, the concentration of charge transport molecules used in any resulting master charge transport spacing layer may be the same or different than the concentration of charge transport molecules used in the adjacent softenable layer. When combining a charge transport material and a film-forming binder to form a charge transport spacing layer, the amount of charge transport material used will depend on the particular charge transport material and its compatibility in the continuous insulating film-forming binder. For example, solubility). Satisfactory results are obtained by using from about 10 to about 50 weight percent of the charge transport material, based on the total weight of the charge transport spacing layer. Somewhat more sophisticated charge transfer materials can also be used, but may result in increased background potential due to insufficient charge transfer. When the concentration of charge transport molecules exceeds about 50%, crystallization of the charge transport molecules in the charge transport layer can occur and charge dark decay can also be high. Furthermore, very high concentrations of charge transport molecules can also impair the mechanical strength, flexibility and integrity of the charge transport layer.

An imageable softenable layer is a layer in which an image of photoconductive particles is formed. The imageable softenable layer includes closely spaced submicron migration marking material embedded just below the surface of an electrically insulating softenable material such as a matrix polymer. The softenable layer may also be doped with a charge transport material which may be the same or different from that used in the charge transport spacing layer described above.

In various variations of the electrostatic printing master used in the present invention, the migration marking material is preferably an electrically photosensitive, photoconductive or any other suitable combination of materials. Typical migration marking materials include, for example, U.S. Pat. No. 4,536,457;
U.S. Patent No. 4,536,458, U.S. Patent No. 3,90
No. 9.262 and No. 3.975.195, the entire disclosures of which are incorporated herein by reference. Particular examples of migration marking materials include selenium and selenium-tellurium alloys. The migration marking material should be particulate and generally closely spaced from each other. Preferred migration marking materials are generally spherical and submicron in diameter. These spherical migration marking materials are well known in the migration imaging art. Excellent results show that approximately 0.0
．． The spherical migration marking material is obtained with a particle size range of 2 to about 0.4 μm, preferably about 0.3 to 0.4 μm. The spherules of migration marking material are spaced slightly apart from each other at a distance of less than half a spherule diameter for maximum optical density and also to facilitate agglomeration and fusion of the migration marking material during the heating process. is preferred. The spheres are also preferably about 0.01 to about 0.1 μm below the outer surface of the softenable layer (the surface remote from the substrate if an overcoating is used). A particularly suitable method for depositing migration marking materials in a softenable layer is described in U.S. Pat. Quote in a book. For purposes of the present invention, it is highly preferred that the migration marking material has a sufficiently low melting point so that its self-diffusion is rapid at the temperatures used during deposition. The deposition temperature should not exceed the degradation temperature of the softenable material, substrate or any other components of the migration imaging member. The term "rapidly" means that particles of migration marking material in contact coalesce preferably within seconds or at most within about two minutes.

The softenable material can be any suitable material that can be softened by solvent vapor. Additionally, in embodiments of electrostatic printing masters, the softenable layer is typically substantially electrically insulating and does not chemically react during the master making and electrostatic printing processes of the present invention. It is something. Although the softenable layer has been described as being coated on a substrate, in some embodiments the softenable layer can itself have sufficient strength and integrity to be substantially self-supporting. Application of electrophoretic forces to the imaging member using the uniform deposition of an electrostatic charge of appropriate polarity on the exposed surface of the softenable layer or optional overcoating layer if a bonded conductive layer is not used. can be easily done. This "double charging" technique is well known in the art. Also, the softenable layer itself may be contacted with a suitable conductive surface during master making and electrostatic printing processes.

Any suitable solvent swellable, softenable material can be used in the softenable layer. Typical swellable and softening materials include styrene acrylate copolymers, polystyrene, alkynd-substituted polystyrenes, styrene-olefin copolymers, styrene-con-n-hexyl methacrylate, intrinsic viscosities of 0.
Custom Synthesized 80/20 Mol% Copolymer of Styrene and Hexyl Methacrylate with 179617 gm, Other Styrene-Hexyl Methacrylate Copolymers, Styrene-Vinyltoluene Copolymers, Polyalpha Methyl Styrene, Copolyesters, Polyesters, Polyurethanes, Polycarbonates, Copolycarbonates , and mixtures or copolymers thereof. These classes of materials are not limiting, but merely illustrative of materials suitable for such softenable layers.

Any suitable charge transport material that can function as a softenable layer material or that can be dissolved or molecularly dispersed in the softenable layer can be used in the softenable layer of the present invention. The charge transport material can improve the charge injection process (for at least one sign of charge) from the electrically insulating marking material to the softenable layer, preferably before or at least during the development stage by softening the softenable layer. ) defined as an electrically insulating film-forming binder or a soluble or molecularly dispersible material (dissolved or molecularly dispersed in an electrically insulating film-forming binder), the modification of which is intended to be an electrically inert insulating material. Made into a softenable layer. The charge transport material may be a hole transport material and/or an electron transport material, ie, the charge transport material may improve the injection of holes and/or electrons from the marking material into the softenable layer. If only one polarity of the implant is modified, for purposes of this invention the sign of the ionic charge used to initially expose the migration marking member to light will most commonly be the sign of the charge by which the implant is modified. It's the same.

Therefore, the use of a particular transport member and a particular marking material combination may improve the injection of holes and/or electrons from the marking particles into the softenable layer compared to a softenable layer that does not contain any transport material. Must. When the charge transport material is dissolved or molecularly dispersed in the insulating film-forming binder, the combination of the charge transport material and the insulating film-forming binder is such that the charge transport material is dissolved in the film-forming binder at a sufficient concentration level. The substance must be able to be contained either directly or in molecular dispersion. In some cases, if the charge transport material is a polymeric film-forming material, there is no need to use an insulating film-forming binder.

Any suitable charge transport material can be used. Charge transport materials are well known in the art. Typical charge transport materials include: U.S. Pat. No. 4,306.0
No. 08, No. 4, No. 304, No. 829, No. 4.233,
No. 384, No. 4.115.116, No. 4,299,8
No. 97, and diamine transport molecules of the type described in No. 4,081,274. Typical diamine transport molecules include N,N-';')eniJLz-N,N'-bis(3s,'tylphenyl)-(1,1'-biphenyl)-4°4'-diamine, , N'-diphenyl-N,
N'-bis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N, N'-bis(2-methylphenyl)-(1, 1'
-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-ethylphenyl)-(1
, 1'-biphenyl)-4,4'-diamine, N, N'
-diphenyl-N,N'-bis(4-ethylphenyl)
-(1゜1'-biphenyl)-4,4'-diamine, N
.

N'-diphenyl-N,N'-bis(4-n-butylphenyl)-(ml'-biphenyl)-4゜4'-diamine, N,N'-diphenyl-N,N'-bis(3- Chlorophenyl)-(1,1'-biphenyl)-4,4'-
Diamine, N,N'-diphenyl-N,N'-bis(4
-chlorophenyl)-(11'-biphenyl)-4,4
'-diamine, N,N'-diphenyl-N,N'-bis(phenylmethyl)-(1,1'-biphenyl]-4゜4'-diamine, N,N,N',N'-tetraphenyl -(2,2'-dimethyl-1,1'-biphenyl)-4
, 4'-diamine, N, N, N'.

N'-tetra-(4-methylphenyl)-(2゜2'-
Dimethyl-1,1'-biphenyl]-4゜4'-diamine, N,N'-diphenyl-N,N'-bis(4-methylphenyl)-C2,2'-dimethyl-1,1'-biphenyl 3-4.4'-diamine, N, N'-diphenyl-N, N'-bis(2-methylphenyl)-(2,2'
-dimethyl-1,1'-biphenyl)-4,4'-diamine, N,N-diphenyl-N,N'-bis(3-
methylphenyl)-(2,2'-dimethyl-1,1'-
biphenyl)-4,4'-diamine, N,N'-diphenyl-N, N'-bis(3-methylphenyl)-lylenyl-1,6-diamif, and the like.

U.S. Pat. No. 4,315,982, 4,278,74
6 and 3,837,851. Typical pyrazoline transport molecules include ■-[lepidyl-(2)-(-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline), ■-[quinolyl-(2)]-3 −(p
-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl-(2))-
3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-'(6-medoxypyridyl (2))-3-(p-dimethylaminostyryl)-5-(p-diethylaminophenyl) phenyl) birapurine, ■-phenyl-3-(p-dimethylaminostyryl)-5-(p-dimethylaminostyryl)pyrazoline, ■-phenyl-3-[p-diethylaminostyryl)
-5-(p-diethylaminostyryl) birapurine and the like.

Substituted fluorene charge transport molecules as described in U.S. Pat. No. 4,245,021. Typical fluorene charge transfer molecules include 9-(4'-diethylaminobenzylidene)fluorene, 9-(4'-methoxybenzylidene)fluorene, 9-(2').

4'-dimethoxybenzylidene)fluorene, 2-nitro-9-benzylidene-fluorene, 2-nitro-9-
(4'-diethylaminobenzylidene)fluorene and the like.

2.5-bis(4-diethylaminophenyl)-1,3
, 4-oxadiazole, birapurin, imidazole,
Oxadiazole transport molecules such as triazoles and the like. Other typical oxadiazole transport molecules are, for example, German Patent Nos. 1,058,836 and 1,060,260.
No. 1,120.8'15.

p-diethylaminobenzaldehyde (diphenylhydrazone), 0-ethoxy-p-diethylaminobenzaldehyde (diphenylhydrazone), 0-methyl-
p-diethylaminobenzaldehyde (diphenylhydrazone), 0-methyl-p-dimethylaminobenzaldehyde (diphenylhydrazone), ■-Naphthalenecarbaldehyde 1-methyl-1-phenylhydrazone, 1-naphthalenecarbaldehyde 1,1-phenylhydrazone , 4-methoxynaphthalene-1-carbaldehyde l-methyl-1-phenylhydrazone and the like. Other typical hydrazone transport molecules are, for example, U.S. Pat.
No. 106, No. 4,338,388, No. 4.387.1
It is described in No. 47.

9-Ethylcarbazole-3-carbaldehyde-1-
Methyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-methyl-1-phenylhydrazone, 9-
Carbazole phenylhydrazone transfer molecules such as ethylcarbazole-3-carbaldehyde-1-ethyl-1-benzyl-1-phenylhydrazone, 9-ethylcarbaldehyde-1,t-diphenylhydrazone, and the like. Other exemplary carbazole phenylhydrazone transport molecules are described in US Patent Sections 4.256,821 and 4.297,426.

Vinyl aromatic polymers such as polyvinylanthracene, polyacenaphthylene; condensation products of formaldehyde with various aromatics, such as the condensate of formaldehyde and 3-bromopyrene; 2.4°7-dolinitrofluorenone; and US 3,6-sinitro N-1-butyl-naphthalimide as described in Patent Section 3.972,717.

Oxadiazole derivatives, such as 2<5>-bis-(p-diethylaminophenyl)oxadiazole-1,3,4, described in U.S. Pat. No. 3,895.944.

Alkyl-bis(N,N-dialkylaminoaryl)methane, cycloalkyl-bis(N,N-dialkylaminoaryl)methane, and cycloalkenyl-bis(N,N-dialkylaminoaryl)methane, as described in U.S. Pat.
Trisubstituted methanes such as bis(N,N-dialkylaminoaryl)methane.

The following formula: (wherein X and Y are cyano groups or alkoxycarbonyl groups, and A, B and W are individually selected from acyl, alkoxycarbonyl, nitro, alkylaminocarbonyl and derivatives thereof. group, m is a number from 0 to 2, and n is a number of O or I)
9-fluorenylidenemethane mR form as described in U.S. Pat. No. 4,474,865. Typical 9-fluorenylidenemethane derivatives belonging to the above formula include (4-n-butoxycarbonyl-9-fluorenylidene)malononetolyl, (4-phenetoxycarbonyl-9-fluorenylidene)malononetolyl, (4-carbitoxycarbonyl-9-fluorenylidene)malononetolyl, (4-carbitoxycarbonyl-9-fluorenylidene) -fluorenylidene) malonontrile, (4
-n-butokiunocarbonyl-2,7-sinitro9-
fluorenylidene) malonate, etc.

Other charge transport materials include poly-1-vinylpyrene, poly-9-vinylanthracene, poly-9-(4-pentenyl)-rubazole, poly-9-(5-hexyl)-carbazole, polymethylenepyrene. , poly-1-(pyrenyl)butadiene; poly-3-aminocarbazole, 1,
3-dibromo-poly-N-vinylcarbazole and 3
, 6-diphyromoboly N-vinylcarbazole; and many other transparent polymers such as those described in U.S. Pat. No. 3,870.516. There are perforated polymeric or non-polymeric transport materials.

The entire disclosures of the 'L' patents relating to charge transport molecules that are soluble or molecularly dispersible in film-forming binders are incorporated herein by reference.

When a charge transport material is combined with an insulating binder to form a softenable layer, the amount of charge transport material used will depend on the compatibility of the particular charge transport material and the softenable layer in the continuous insulating film-forming binder phase. (e.g. solubility) etc. Satisfactory results are obtained using from about 8 to about 50 weight percent charge transport material, based on the total weight of the softenable layer. Particularly preferred charge transport molecules have the following formula: where X, Y and Z are selected from the group consisting of hydrogen, alkyl groups having from 1 to 20 carbon atoms, and chlorine;
At least one of X, Y and Z is 1 to 2, respectively
is a molecule having an alkyl group with 0 carbon atoms or chlorine). When Y and Z are hydrogen, the compound is N,N'-bis(alkylphenyl)-(1
,1'-biphenyl)-4,4'-diamine (alkyl is for example; methyl, ethyl, propyl, n-butyl, etc.), or the compound is N,N'-diphenyl-N
, N'-bis(chlorophenyl)-(1,1'-biphenyl]-4°4'-diamine.

Excellent results, including exceptional storage stability, can be achieved when the softenable layer contains from about 10 to about 40 weight percent of the diamine compound described above, based on the total weight of the softenable layer. Best results indicate that the softenable layer contains from about 16 to about 40 weight percent N,N'-diphenyl-N,N'-bis(3#-methylphenyl) to (1,1') based on the total weight of the softenable layer. -biphenyl)-4,4'-diamine. When the softening layer contains less than about 8% by weight of the above diamine compound based on the total weight of the softening outer layer, D min becomes significantly higher and D 11
The photodischarge in the mX region is also small due to ineffective charge transport, reducing the electrostatic contrast potential in electrostatic printing.

When the concentration of the charge transport material is greater than about 50% by weight of the diamine compound described above, based on the total weight of softenable N, the mechanical strength, flexibility and integrity of the softenable layer are somewhat degraded and charge dark decay occurs. It also becomes more expensive.

Furthermore, very high concentrations of the diamine compounds described above can also cause crystallization of the compounds in the softenable layer.

The charge transport material may be incorporated into the softenable layer and the optional charge transport spacing layer by any suitable method. For example, the charge transport material can be mixed with the softenable layer or spacing layer components by dissolving them in a common solvent. If desired, mixtures of each solvent for the softenable layer or spacing layer can be used to facilitate mixing or coating.

The optional adhesive layer, optional charge transport spacing layer, and softenable layer can be applied to the substrate by any suitable coating method. In these multilayer coatings, appropriate restrictions should be placed to prevent one layer of coating from dissolving the underlying layer. This can be achieved by appropriate selection of the film-forming binder material and its solvent or solvent mixture. Typical coating methods include the draw rod method, spray method, extrusion method, dipping method, gravure roll method, wire winding method,
There are air knife coating methods, etc.

The thicknesses of the adhesive layer and charge transport spacing layer are as described above. The thickness of the softenable layer depends on whether a charge transport spacing layer is used.

When using a charge transport spacing layer having a thickness in the range of 1 to 25 μm, the thickness of the adherent softenable layer after the drying or curing step is about 2 to 30 μm with a total thickness in the range of about 3 to 30 μm. It is preferably in the range of 5 μm. A thickness of the softenable layer of less than 2 μm may result in insufficient electrostatic contrast potential in developing the latent image during electrostatic printing. The use of a charge transport layer obviates the need for a softenable layer thicker than about 5 μm. However, if a charge transport layer is not used, the thickness of the softenable layer preferably ranges from about 3 to 30 micrometers to provide a sufficiently high electrostatic contrast potential to suit the particular application. Approximately 3
Layers thicker than 0 μm can also be used, but no further improvement in print quality is obtained.

The inclusion of charge transport materials in the softenable and charge transport layers provides the imaging member of the present invention with the ability to form optically sign-reversed images and its use as a master for electrostatic printing.

Any suitable solvent for the softenable material of the softenable layer can be used. Upon contact, the solvent should soften the softenable layer sufficiently to cause the exposed migration marking material to retain a slight net charge, and this slight net charge should cause only slight agglomeration, coalescence, or combinations thereof of the exposed migration marking material. occurs during the subsequent resistance reduction step and/or allows at most only a slight migration in the depths of the migration marking material towards the substrate and furthermore in the softenable layer. The non-exposed marking material is substantially agglomerated and fused while reducing the marking material's resistance to migration. Typical solvents include various ketones, aliphatic esters, halogenated aliphatics and mixtures thereof.

The softenable layer may be softened sufficiently to allow a slight imagewise deep migration of the migration marking material towards the substrate by contacting it with a vapor or liquid of a solvent or solvent mixture. If necessary,
The solvent mixture may include a mixture of a poor solvent and a good solvent for the softening substance to control the degree of softening of the softening substance within a certain period of time. Typical combinations of softeners and solvents or solvent mixtures include styrene ethyl acrylate copolymer and methyl ethyl ketone vehicle, styrene hexyl methacrylate copolymer and methyl ethyl ketone solvent, styrene hexyl methacrylate copolymer and ethyl acetate solvent, and styrene to bovine syl methacrylate copolymer. and diethyl ketone solvent, styrene hexyl methacrylate copolymer and methylene chloride solvent, styrene butyl methacrylate copolymer and 1.1.1-)lichloroethane solvent, styrene hexyl methacrylate copolymer and toluene and isopropanol solvent mixture, styrene butadiene There are copolymers and ethyl acetate and butyl acetate solvent mixtures. If an optional Ocher coating layer is used on top of the softenable layer to improve wear resistance, this overcoating layer should be permeable to the solvent vapor used and the solvent treatment time should be The solvent vapor can soften the softenable layer enough to cause the exposed migration marking material to retain a small net charge, and this small net charge can cause the exposed migration marking material to have only a small amount of agglomeration, fusion, or a combination thereof. occurs during the subsequent resistance reduction step and/or allows at most only a slight migration in the image shape in the depths of the migration marking material towards the substrate and, furthermore, softens the softening layer. The non-exposed marking material must be substantially agglomerated and fused while reducing the resistance to migration of the marking material therein.

The optional overcoating layer may be substantially electrically insulating or have other suitable properties.

The overcoating layer should be substantially transparent, at least in the spectral region where electromagnetic radiation is used in the imagewise exposure step of an imaging process and the uniform exposure step of an electrostatic printing process. The overcoating is continuous and preferably has a thickness of up to about 1-2 μm.

Preferably, the overcoating is about 0.1 to about 0.
．． It should have a thickness of 5 μm to minimize residual charge build-up. Overcoating layers thicker than about 1-2 μm can also be used, but can result in cycle amps due to the charge trapping tendency that occurs in the overcoating layer when multi-sided prints are made during electrostatic printing. Typical overcoating materials include acrylic-styrene copolymers, methacrylate polymers, methacrylate copolymers, styrene-butyl methacrylate copolymers butyl methacrylate resins, vinyl chloride copolymers, fluorinated homo- or copolymers, high molecular weight polyvinyl acetate, organosiloxane polymers and copolymers, Examples include polyester, polycarbonate, polyamide, polyvinyltoluene, etc. The overcoating layer should protect the softenable layer 18 and provide greater resistance to the adverse effects of abrasion during handling, imaging, and electrostatic printing. The overcoating layer preferably protects the softenable layer 18. The overcoating layer also has a non-tacky outer surface that provides improved resistance to toner film formation during toner application and/or cleaning. Non-stick properties may be inherent in the overcoating layer or may be imparted to the overcoating layer by the inclusion of other layers or non-stick material components.

These non-stick materials should not degrade the film-forming components of the overcoating and should preferably have a surface energy of about 20 ergs/cd or less. Typical non-stick materials include fatty acids, salts and esters, fluorocarbons, silicones, and the like.

The overcoating can be applied by any suitable method such as the draw rod method, spraying, dipping, melting, extrusion or gravure coating. It will be appreciated that these supercoating layers protect the electrostatic printing master before imaging, during imaging, after portion +4 is imaged, and during electrostatic printing.

Again, with respect to the electrostatic printing master precursor members illustrated in FIGS. 1, 2, and 3, these master precursor members may be charged and imagewise exposed prior to application of solvent vapor. Next, develop by heating. If substrate 12, conductive layer 14, and adhesive layer 22 are optically transparent, these members, when imaged, provide for selective aggregation and coalescence of migration marking material in unexposed areas. Highly transparent to visible images. The vapor is applied to the imaging member after imagewise exposure and before the final thermal development step to improve the exceptionally low D m of the electrostatic printing master used in the electrostatic printing process of the present invention.
i should be achieved.

In FIG. 9, an electrostatic printing master precursor member includes a substrate 52 having a conductive coating 54, a softenable layer 56, and a layer of migration marking material 58 IE applied to the surface of the softenable layer 56. shown as including. The electrostatic latent image is formed on the imaging member by uniformly electrostatically charging the imaging member and subjecting the charged member to activating electromagnetic radiation before dark decay of the substantially uniform charge occurs. It can be formed by exposing to light as shown in FIG. The imaging member is shown in FIG.
It is shown as being electrostatically positively charged by a corona charging device 6.0. If the substrate 52 is conductive or has a conductive coating 54, the conductive layer is grounded or maintained at a predetermined potential during electrostatic charging. Another method of charging a member having an insulating substrate rather than a conductive substrate is to electrostatically charge both sides of the member to surface potentials of opposite polarity.

In FIG. 10, the charged, unimaged member is shown exposed to activating electromagnetic radiation 62 in region 63, thereby forming an electrostatic latent image on the master. Imagewise exposure to form an electrostatic latent image on the electrostatic printing master precursor member should occur prior to substantial dark decay of the deposited surface charge. Satisfactory results are obtained when the dark decay is less than about 50% of the initial charge.

That is, the expression "before substantial decay" means that the dark decay is less than about 50% of the initial charge. Approximately 25% of the initial charge
% dark decay is preferred for optimal imaging of the electrostatic printing master precursor member.

The electrostatic printing master having the electrostatic latent image thereon is then exposed to solvent vapor 64 (indicated by the black dots), as shown in FIG. The steam exposure time depends on the solubility of the softenable layer in the solvent, the type of solvent vapor, the ambient temperature and the concentration of the solvent vapor.

Furthermore, the presence or absence of an overcoating on the softenable layer can also affect exposure time.

The charge transport molecules in the softenable layer and the vapor treatment function by limiting the photoexcited charge on the exposed migration marking particles (see Figure 10) to a reproducible but very small level after the vapor treatment step. This small level of net charge results in only slight agglomeration of the exposed migration marking particles during the subsequent heating process.
Allow for fusion or combinations thereof. This small level of net charge also causes the exposed particles to migrate away from the softening surface away from the substrate, slightly increasing the separation between adjacent migration marking particles.

This gives the D max area. In the unexposed or unexposed areas, any surface charge becomes discharged by vapor exposure.

In FIG. 12, the latent image is further developed by the application of heat 66, shown sub-irradiated to the softenable material 56, to reduce the resistance of the softenable material to migration of the particulate marking material, thereby effecting softening. do. However, the viscosity of the softenable material is such that due to the synergistic effect of steam and heat softening, these unexposed particles, which have no residual charges that repel each other and are still very close to each other, randomly diffuse and close together. They contact and drop so far that they can actually coalesce very rapidly to form a very small number of but fairly large spheres 70 . These agglomerated/fused particles are quite widely separated and have a very low D7 so large that these particles are essentially invisible below the wavelength of visible light.
□Give 7. As mentioned above, the exposed particles are still slightly charged and/or slightly migrated by the solvent vapor treatment described above, and only slight agglomeration/coalescence and/or slight migration occurs. The positions of these exposed particles remain substantially unchanged from the positions produced during the steaming step of FIG. Thus, in FIG. 12, the migration marking material is shown slightly agglomerated/fused and/or migrated in the exposed areas and substantially agglomerated/fused in the unexposed areas. The exposed and unexposed areas correspond to the formation of the electrostatic latent image shown in FIGS. 10 and 11. That is, this method for producing an electrostatic printing master produces an optically positive image from a positive original image or an optically positive image from a negative original image when an optical lens system is used for image-forming exposure. , optically forms a sign-reversed image.

As will be appreciated, imagewise exposure may also be effected by means other than optical lens systems, for example by raster output scanning devices such as laser writers. Satisfactory results were obtained when the solvent was methyl ethyl ketone and the uncoated softening layer was 0.179 dj! Custom synthesized 80/20 mol% copolymer of styrene and hexyl methacrylate with intrinsic viscosity of /g- and N,N'-diphenyl-N,N'-bis(3#-methylphenyl)-(1
, 1'-biphenyl)4,4'-diamine,
This is achieved with steam exposure times of about 10 seconds to about 2 minutes at 21°C (longer times at lower temperatures) and solvent vapor partial pressures of about 20 to about 80 m+% Hg. Tests for satisfactory combinations of time, temperature and vapor concentration are optical contrast density and electrostatic contrast potential for electrostatic printing.

The imaged electrostatic printing master shown in FIG.
Shown without any optional component layers similar to those shown in the figure. If desired, another master similar to that shown in FIGS. 1 or 2 may be used in place of the coating member shown in FIGS. 3 and 12.

The imaged electrostatic printing master shown in FIG.
It is highly transparent to visible light in the unexposed areas due to substantial aggregation and coalescence of the migration marking material in the unexposed areas. Obtained in the exposed area 7.7
is almost as low as the optical density of the transparent substrate beneath the softenable layer. Also, the D matx of the exposed areas is high as only slight agglomeration/fusion and/or slight migration of exposed particles occurs. That is, optically sign-reversed images with high contrast densities in the range 1.0 to 1.3 are obtained for electrostatic printing masters. Furthermore, excellent resolution such as 228 line pairs/trundle is achieved on the electrostatic printing master.

The vapor should be applied to the master after the imagewise exposure step and before the final thermal development step to achieve a highly light transmissive image of the vapor.

In the steam-heat development sign reversal image formation method for producing the master used in the electrostatic printing method of the present invention, in order to obtain the excellent results of the present invention, it is necessary to Most of the photoexcited charge carriers (5
0-95%, preferably 90-95!1 fi) should be injected from the exposed migration imaging particles (
It is believed that during or before the initial stages of development due to the softening of the softenable layer). After loss (during or before the initial step of development) of the other sign of photoexcited charge (either by injection from the particle or by neutralization by the charge initially applied to the surface),
Only a small net charge remains in the exposed migrated imaging particles. Charge injection of the first sign of charge is achieved by including a charge transport layer in the softenable layer of the master. Due to the extremely small net charge of the exposed area,
Only slight agglomeration/fusion and/or slight migration of exposed particles occurs. Thus, the optical density is approximately 1.8-1
．． Only slightly compared to the initial value of 9, e.g.
．． 0 to 1.7 (preferably 1.2 to 1.7 or more, more preferably 1.4 to 1.7 or more). Although a small net charge and/or a small migration in the particles is necessary to obtain the excellent results of the present invention, it must not be excessive or the final sign-reversed image D as
, (and the resulting contrast density) decreases below the above value. In conventional migration imaging members that do not contain any charge transport material in the softenable layer, the exposed migration imaging particles are processed using a steam treatment-thermal development step to perform the electrostatic printing process of the present invention. When making the master for use, it acquires a significant net charge and migrates significantly to form regions of low optical density instead of regions of high optical density.

Furthermore, in the steam-heat development sign reversal imaging method for preparing the electrostatic printing master of the present invention, the unexposed particles become uncharged and are used during (or before) the steam treatment step. during any heat treatment step), but remains substantially uncharged in a monomolecular form, allowing substantial aggregation and fusion during the final heating step after the steam treatment step. Even in conventional migration imaging members that do not include any charge transport material in the softenable layer, the unexposed particles generally remain substantially uncharged.

That is, the charge transport material in the master used in the electrostatic printing method of the present invention primarily changes the electrostatic charge of the exposed particles.

In conventional migration imaging members, ie, without any charge transport material in the softenable layer, exposed migration imaging particles acquire a net positive charge upon vapor exposure. This resulting charge can be reduced to a reproducible low level if electron injection into the migrating imaging particles also occurs during or after exposure. This can be achieved by electron injection molecules in a continuous matrix of softenable layers.

To achieve this charge injection, the highest occupied molecular orbital (HOMO) of at least one substance in the continuous matrix of the softenable layer must not be too far below the valence band top of the migration imaging particles. Preferably, it may be above the valence band top, otherwise this energy barrier would impede injection even when an electric field assists. According to this mechanism, electron injection into the exposed migration imaging particles is sufficient to establish the resulting near-neutrality. - On the other hand, the unexposed migrating imaging particles must remain substantially neutral and not migrate out of the monolayer upon vapor exposure, otherwise agglomeration and coalescence will be extremely difficult. In order to prevent possible dark charging (and possibly to prevent total near-neutrality as a result of exposure of the migrating imaging particles), the material in the matrix of the softening layer absorbs the valence band of the migrating imaging particles. HOM can't get too far above
O should not be present, otherwise an unacceptable amount of charge exchange will occur with the unexposed migrating imaging particles, causing these particles to migrate haphazardly upon vapor exposure. However, this negative effect of a relatively high presence of HOMO can be offset using a relatively low concentration of charge transport material, which is still sufficient to provide sufficient electron injection into the exposed particles. That is, in order to obtain satisfactory results with the preferred steam-heat development imaging method described above for preparing an electrostatic printing master, the HOMO of at least one substance in the matrix of the softenable layer must be such that the valence electrons of the migration imaging particles are It should not be significantly below the top of the band, preferably it can be above the top of the valence band, and the HOMO of at least one charge transport material
is substantially above the top of the valence band of the migration imaging particles, the charge transport material should be used in relatively low concentrations. The acceptable concentration of charge transport material will generally decrease as a function of the difference between its HOMO and the valence band of the migration imaging particles. The appropriate concentration of charge transport material can be determined experimentally by maximizing the optical contrast density of the resulting sign-reversed image and the electrostatic contrast potential required for electrostatic printing as a function of concentration. For example, the energy difference between the HOMO and the valence band is approximately 0.9 to 1. It should decrease to about 20% or less as the voltage increases above OeV. The statement that the HOMO should not lie "significantly below" the valence band means that the HOMO should not lie more than O,leV below the valence band, preferably more than 0.05 eV; of course, The HOMO can be above the valence band as described above. Charge transport should also extend through the matrix of the softenable layer upon exposure to produce the necessary electrostatic contrast potential of the latent image and to ensure freedom from residual charge accumulation during rapid cycling operations.

If a particular combination of charge transport material and softenable layer material requires the use of a relatively low concentration of charge transport material in the softenable layer to obtain good imaging, the The negative effect of relatively low concentrations of charge transport material on good charge transport can be offset by using a thin softenable layer with a separate thick charge transport layer.

The HOMO of most polymers used as softening layers in migration imaging members, such as 80/20 mole % copolymers of styrene and hexyl methacrylate, lies well below the valence band of amorphous selenium migration imaging particles. Existing. Under these circumstances,
There is non-negligible electron injection into the migrating imaging particles during exposure unless a charge transport material (ie, one with an appropriate HOMO) is carefully added.

The above effect is due to N,N'-diphenyl-N,N'-bis(3"-methylphenyl)-(11'-biphenyl)
-4,4'-diamine, 3-methyldiphenylamine,
4,4'-Hendylidenebis(N,N-diethyl-m-
U.S. Pat. No. 4,536,457, which incorporates toluidene and p-diethylaminohenzaldehyde (diphenylhydrazone) in a conventional softenable layer matrix.
It is suggested in the issue. HOM of each of these substances
All O's are shown in the potential energy diagram as being in the lower half of the valence band of amorphous selenium. The first two of R, i.e., N, N'~diphenyl-N, N'
-Bis(3″-methylphenyl)(1,1″-biphenyl)-4,4″-diamine and 3=methyldiphenylamine give good steam-heat development sign reversal images at about 20% concentration level. N.

N'-diphenyl-N,N'-bis(3#-methylphenyl)-(1,1'-biphenyl)-4,'4'-diamine gives good injection and transport during exposure (near total film voltage 3-methyldiphenylamine gives good injection but relatively poor transport (results in relatively high residual voltage), while 3-methyldiphenylamine gives good injection but relatively poor transport (results in relatively high residual voltage), and good image transfer after injection and before development. It was shown that it is not critical for formation.

4.4'-Benzylidenebi (N, N'-Jedjiru m-
toluidene) and p-diedylaminobenzaldehyde-(diphenylhydrazone), whose HOMOs are above the valence band of amorphous selenium, and when included at a level of about 20%, upon exposure (the corotron charge of the film Even without ibis) gave only a disordered transition (to an optical density of approximately 1.4). However, the concentration is about 3%.
4.4'-henjiridenbis (
N, N-diethyl-m-1-luidene) and p-diethylaminohenzaldehyde (diphenylhydrazone)
Both obtained steam-heating sign inversion images.

The explanation below relates to the situation of reversal of negative corona charge.

Due to the negative corona charging of the normal migration imaging portion +1 without any charge transport material in the softenable layer, the exposed migration imaging particles acquire a substantial negative charge upon vapor exposure. This substantial negative charge acquisition must be prevented in order to obtain satisfactory results with the steam-thermal development process used in the electrostatic printing process of the present invention. The necessary hole injection into the migration imaging particles to prevent this is based on the lowest unoccupied molecular orbital (LLJMO) of at least one matrix component in the continuous matrix of the softenable layer (i.e. -ReMO)
It is believed that this can occur if the migration imaging particle is below the bottom (or at least not significantly above the bottom) of the conduction band.

Furthermore, to prevent undesirable dark charging of the migrating imaging particles, the substantial matrix components should not have an LU MO that is too far below the conduction band of the migrating imaging particles.

L U M O of any significant matrix component
If the matrix component is substantially below the conduction band of the migration imaging particles, this matrix component should be used at relatively low concentrations. The acceptable concentration of the charge transport substance is L.
It will generally decrease as a function of the difference between the conduction band of the UMO and the migration imaging particles. Suitable for charge transport materials? Gastric strength can be determined experimentally by maximizing the optical contrast density of the sign-reversed image obtained and the electrostatic contrast potential required for electrostatic printing as a function of concentration. According to this mechanism, it is believed that hole injection into exposed migration imaging particles establishes the resulting near-neutrality. It should be noted that typical polymeric materials used as softening layers in migration imaging members, such as the 80/20 mole % copolymer of styrene and hexyl methacrylate L U M O , are below the conduction band of amorphous selenium. Therefore, particle hole injection upon exposure should not be ignored unless a charge transport material (i.e. one with suitable LtJMo) is carefully added.

Combinations of charge transport materials and migration imaging particles as described above or below that satisfy the HOMO or LUMO conditions described above are, of course, compatible with any softenable material used in matrices, laths, etc. The requirements should also be met. For example, if the charge transport material is to be dissolved or molecularly dispersed in an insulative film-forming binder, the combination of the charge transport material and the insulating film-forming binder may require a sufficient concentration of the charge transport material in the film-forming binder. It must be possible to contain it in a dissolved or molecularly dispersed state. If desired, there is no need to use an insulating film-forming binder if the charge transport material is a polymeric film-forming material.

The produced electrostatic printing master can then be used in an electrostatic printing method in which the electrostatic printing master is uniformly charged by corona charging. The polarity of the corona charge used in electrostatic printing depends on whether a tag transport material or an electron transport material is included in the softenable layer and the charge transport layer. Positive corona charging is used with hole transport materials in the softenable layer and charge transport layer. When electron transport materials are used in the softenable and charge transport layers, the electrostatic printing master is uniformly negatively charged. The electrostatic printing master is the first for illustrative purposes.
It is uniformly positively charged using a corona charging device as shown in Figure 3.

The charged imaging member is then uniformly flash exposed to form an electrostatic latent image as shown in FIG.

As mentioned above, due to the difference in relative size and number of migration marking particles, the DmaXt'M and Dm+n'RI areas of the electrostatic printing master of the present invention are uniformly charged. When exposed uniformly to light, it shows not only a large difference in optical density (the Dmixa region is highly absorbing and a D187 region is transparent) but also a large difference in photodischarge. That is, when the electrostatic printing master is uniformly charged and exposed to electromagnetic radiation for activation,
Photodischarge occurs primarily in the D□ region, with substantially less photodischarge occurring in the Dl region of the electrostatic printing master. 7 regions, giving an electrostatic latent image. The charge remains substantially in the Dmi region and substantially dissipates in the Dl,1 region. The activating radiation of the uniform exposure step should be substantially absorbed by the migration marking particles to produce a substantial photodischarge in the D max region. The activating electromagnetic radiation used in the uniform exposure process should be in the spectral region where the migration marking particles photoexcite charge carriers.

Monochromatic light in the 300-500 nanometer (nm) range is preferred for selenium particles and maximizes the electrostatic contrast potential of the electrostatic latent image. The exposure energy should be such that the desired and/or optimal electrostatic contrast potential is obtained. That is, the electrostatic printing master according to the present invention can be considered an imagewise "stained" photoreceptor, with the D and regions being relatively good photoreceptors, and the D a i. The area is a relatively poor photoreceptor. The terms "poor" and "good" are intended to refer to two photoreceptors in which the difference in background potential differs by at least 30% and preferably at least 40% of the initially applied surface potential; a good photoreceptor is It shows high photodischarge. This imagewise "stained" photoreceptor has different photodischarge properties (and photosensitivity) caused by permanent structural changes in the migration marking material in the softenable layer.

In general, the D+*ix region exhibits substantial photodischarge when electrostatically charged and exposed to light, and is substantially absorptive to activating electromagnetic radiation in the region of the spectrum in which the migration marking particles photoexcite charge carriers. It is opaque.

The Dm=n'J4 region exhibits a substantially smaller photodischarge and its background potential differs by at least about 30%, preferably at least 40%, of the initially applied surface potential compared to the Dam region, and The migration marking particles have substantially low absorption for activating electromagnetic radiation in the spectral region in which charge carriers are photoexcited. Since the electrostatic latent image is re-excited with each printing cycle as in conventional photoreceptors, this greatly improved electrostatic printing master structure of the present invention is similar to certain prior art masters, such as U.S. Pat. .407,918 (in which the lifetime of the electrostatic latent image depends on the insulating ability of the charge retentive layer) - without deterioration of the electrostatic latent image; Ensure excellent copy quality. It should be noted that although the visible image on the electrostatic printing master is an optically sign-reversed image of the original image (if the master is formed by lens assembly exposure instead of laser scanning), the electrostatic charge The image is the same as the original image (sign-preserving property).

The latent electrostatic image is then developed with toner particles to form a toner image corresponding to the latent electrostatic image. Developing (with toner)
The process is the same as that commonly used in electrostatographic imaging. Any suitable conventional electrostatographic dry or liquid developer containing electrostatically attractive marking particles can be used to develop the electrostatic latent image on the electrostatic printing °7 star of the present invention. Typical dry toners have a particle size of about 6 to about 20 μm. Typical liquid toners are about 0.1 to about 0.3 μm
It has a particle size of The particle size of the toner particles affects the resolution of the print. In applications requiring extremely high resolution, such as color proofing and color printing, liquid toner is generally preferred due to its much smaller particle size, which provides better resolution of fine halftone dots.
Forms a four-color image without excessive thickness in dense black areas.

Transferable liquid developer toners are typically about 2 μm in diameter. Toner particles may be deposited onto the imaging surface of the electrostatic printing master of the present invention using conventional electrostatographic development techniques.

The present invention extends to development with a dry two-component developer.

A typical two-component developer includes toner particles and carrier particles. Typical toner particles can have any composition suitable for developing an electrostatic latent image, such as a composition that includes a resin and a colorant. Typical toner resins include polyesters, polyamides, epoxies, polyurethanes, diolefins, vinyl resins, and polymeric transesterification products of dicarboxylic acids and diols, including diphenols. Examples of vinyl monomers include styrene, p-chlorostyrene, and vinylnaphthalene; unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; acetic acid. Vinyl, vinyl propionate, vinyl benzoate and vinyl butyrate; methyl acrylate, ethyl acrylate,
n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-
Vinyl esters such as esters of monocarboxylic acids including chloroethyl acrylate, phenyl acrylate, methyl alpha chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc.; acrylonitrile, methacrylonitrile, acrylamide; vinyl 7 methyl ether, vinyl Vinyl ether necks including isobutyl ether and vinyl ethyl ether: vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isobutyl ketone; N-vinylindole and N-vinyl pyrrolidone; styrene butadiene; and mixtures of these monomers, etc. There is. The resin generally comprises about 30 to 30% of the toner composition.
Although present in an amount of about 90% by weight, greater or lesser amounts of the resin can be used so long as the objectives of the invention are achieved.

Any suitable pigment or dye can be used in the toner particles. Typical pigments or dyes include carbon black,
Nigrosine dye, aniline blue, magnetite, and mixtures thereof, with carbon blank being the preferred colorant. The pigment is preferably present in an amount sufficient to provide a highly pigmented toner composition that enables the formation of a clear visible image on the recording member. - Within the shell, the pigment particles are present in an amount of from about 1 to about 20% by weight based on the total weight of the toner composition, although greater or lesser amounts of pigment particles may be used as long as the objectives of the invention are achieved. Can be used.

Other color toner pigments include red, green, blue, brown, magenta, cyan, and yellow particles,
There are also mixtures of these. Specific examples of suitable magenta pigments include 2,9-dimethyl substituted quinacridone and Color Index Cl60710. Examples include anthraquinone dyes listed as CI Disperse Dread 15, Cl26050 in the color index, and diazo dyes listed as CI Zurchen Red 19. Specific examples of suitable cyan pigments include tetra-4-
(octadecylsulfonamide) phthalocyanine, X-copper phthalocyanine listed as Cl74160°CI Pigment Blue in the Color Index, and anthradanethrene blue listed as C169810 and Special Blue X-2137 in the Color Index. Specific examples of yellow pigments that can be used include sialite yellow 3,3-dichlorohenzidine acetoacetanilide, with a color index of C11.
2700, a monoaz pigment listed as CI Zurghent Yellow 16, with Freon Yellow S E/GL N in the color index.

Nitrophenylamine sulfonamide, 2゜5-dimethoxy-4-sulfonanilide phenylaz-4'-chloro-2,5-dimethoxyaceto-acetanilide, Permanent Yellow FGL, etc. listed as CI Disburst Yellow 33 be. These color pigments may be present in amounts ranging from about 15 to about 20, based on the weight of the toner resin particles.
．． It is present in -a in an amount of 5% by weight, but smaller or larger amounts can be used while still meeting the objectives of the invention.

When the pigment particles are magnetite, the magnetite comprises a mixture of iron oxides (Fe304), such as that commercially available as Mapico Black. These pigments are present in the toner composition in an amount of about 10 to about 70% by weight, preferably about 20 to about 50% by weight, so long as the objects of the invention are achieved.
These pigments may be present in greater or lesser amounts.

The toner composition can be prepared in any suitable manner.

For example, the components of the dry toner may be mixed in a ball mill with stirring steel beads added in an amount approximately five times the weight of the toner. The ball mill is approximately 120 feet (364,
8 cm)/min for approximately 30 minutes, after which time the steel beads are removed. Dry toner for two-component developer is approximately 6~
It has an average particle size of about 20 IJm.

Any suitable external additives can also be used in the dry toner particles. Although the amount of external additive can be scaled in terms of weight percent of the toner composition, the amount itself is not included when calculating the percent composition of the toner. For example, a toner composition that includes resin, pigment, and external additives may contain 80% resin and 20% pigment by weight, with the external additives reported as a % of the total weight of resin and pigment. External additives include straight silica, colloidal silica (e.g. Aerosil R972 available from Degusosa), secondary oxide
Electrostatographic materials including iron, uniline, polypropylene wax, polymethyl methacrylate, zinc stearate, chromium oxide, aluminum oxide, stearic acid, polyvinylidene fluoride (e.g., Quinal, available from Bensalt Chemicals Corporation), etc. There may be optional additives used. External additives may be present in any suitable amount so long as the objectives of the invention are achieved.

Any suitable carrier particles can be used with the toner particles. Typical carrier particles include particulate zircon, steel, nickel, iron ferrite, and the like. Other typical carrier particles include nickel granular carriers as disclosed in US Pat. No. 3,847,604, the entire disclosure of which is incorporated herein by reference. These carriers are nodular nickel bead carriers characterized by a reproducible textured surface, giving particles with relatively large external areas. The diameter of the carrier particles can vary, but is generally from about 50 to about 1.000 microns, thus providing the particles with sufficient density and inertia to avoid electrostatic image sticking during the development process. The carrier particles may have a coated surface. Typical coating materials include, for example, U.S. Pat. No. 3,526,533
No. 3,849.186 and No. 3.942,97
There are polymers and terpolymers that include fluoropolymers, such as polyvinylidene fluoride, as described in US Pat. The toner may be present in the two-component developer in an amount equal to, for example, about 1 to about 3% by weight of the carrier, preferably in an amount equal to about 3% by weight of the carrier.

Typical dry toners are described, for example, in U.S. Patent No. 2.788
, No. 288, No. 3.079. , No. 342 and Reissue Patent No. 25,136, the disclosures of which are incorporated herein in their entirety. In some cases, development may be performed with a liquid developer. Liquid developers are, for example,
U.S. Patent Nos. 2,890.174 and 2.899,
No. 335. Liquid developers may include water-based or oil-based inks. Liquid developers include both inks containing water-soluble or oil-soluble dyeing substances and pigmented inks. Typical dye materials include methylene blue, commercially available from Eastman Kodasoku Company, Brilliant Yellow, commercially available from Harako Chemical Company, Permanga '411 Power' J Rum, Ferric Chloride, Meddi. The following three are available from Allite YMical Co., Ltd. 7. Typical face color: 1 is carbon black,
Good fight, oil smoke, bone charcoal, charcoal, titanium dioxide, own ship, oxidation! 1F lead, zinc sulfide, iron oxide, chromium oxide, lead cucomate, zinc chromate, cadmium yellow, Katominiu J, red, lead moon, antimony dioxide 1. Examples include magnesium silicate, calcium carbonate, calcium silicate, phthalocyanines, heridines, naphthols, and toluidines. The liquid developer composition may include a finely divided opaque powder, a high resistance liquid, and an anti-agglomeration component. A typical high-resistance liquid C is Isopar.
Carbon tetrachloride, gelosene, benzene, trichloroethyl
There are organic insulating liquids such as capacitors. Other liquid developer components or additives include carboxyvinyl polymer, polyvinylpyrrolidone, methyl vinyl ether-anhydrous male
Vinyl resins such as 1'-acid copolymers, polyvinyl alcohol: sodium chloride-1-ethyl cellulose, bitroxypropyl methyl cellulose, human 1-x ethyl cellulose, methyl cellulose, esters of these celluloses and Cellulose derivatives like ether; alkaline possible? Tolerance Tamba<
In fact, there are casein, gelatin; and acrylates such as ammonium polyacrylate and sodium polyacrylate.

Any suitable conventional electrostatographic development process may be used to deposit the toner particles onto the electrostatic latent image on the imaging surface of the electrostatic printing master of this invention. Well known electrostatographic development methods include magnetic brush methods, powder coating methods, cassgate methods, powder coating methods, electrophoretic methods and similar development methods. The cascade development method is described in U.S. Pat.
, 618,552, and the powder coating development process is described in more detail in U.S. Pat. No. 2,725,305, 2.
No. 918,910 and No. 3,015,305, and the 6-brush development method is more fully described in U.S. Pat. No. 2,791,949,
Additionally, liquid development methods are described in more detail in US Pat. No. 3,084,043. All patents related to these toners, developers, and development methods are incorporated herein by reference.

(The multicolor toner image can be transferred to a receiving member, such as paper, by any suitable method commonly used in electrostatographic reproduction, such as corona transfer, pressure transfer, adhesive transfer, bias roll transfer, etc.). Standard corona transfer involves contacting attached toner particles with a paper sheet and applying an electrostatic charge to the side of the sheet opposite the toner particles.

A single wire corotron with an applied potential of about 5000 to about 8000 volts provides satisfactory transfer.

After transfer, the transferred toner image can be fused to the receiving sheet.

The fixing step is also the same as that normally used in electrostatographic image formation. Typical well-known electrostatographic fusing methods include heated roll fusing, flash fusing, oven fusing, lamination, adhesive spray fusing, and the like.

Because the electrostatic printing master forms identical successive images in exactly the same area, there is no need to erase the electrostatic latent image between successive imaging cycles. However, if necessary, it may optionally be erased by conventional electrostatographic erasing techniques. For example, uniform exposure of an electrostatic printing master to intense light discharges both image and non-image areas of the master. Typical light intensities that can be used for erasing range from about 10 times to about 300 times the light intensity used in the uniform exposure process.

Another well known method involves exposing the imaging surface to an AC corona discharge to neutralize any residual charge on the master.

Typical potentials applied to the corona beam of an AC corona eraser may range from about 3 to about 10 kilopoles.

If necessary, the surface of the electrostatic printing master may be cleaned. Any suitable cleaning process commonly used in electrostatographic imaging can be used to clean the electrostatic printing masters of the present invention. Typical well-known electrostatographic cleaning methods include brush cleaning, blade cleaning, web cleaning, and the like.

After transferring the adhered toner image from the master to the receiving member, the master is cycled through additional uniform charging, uniform exposure, development, and transfer steps to create additional images, with or without erasing and cleaning steps. The forming portion can form a receptacle.

Unlike some conventional electrostatic printing masters, the master used in the electrostatic printing method of the present invention has its entire imaging surface insulating (i.e., the fringe electric field from the insulating region Since there is no insulating image on the metal conductor to repel ions to adjacent conductive regions), it can be uniformly charged to its full potential. This provides a high contrast potential and high resolution electrostatic image on the master. That is, a high quality image with high contrast density and high resolution can be obtained. Thus, the problems of low contrast potential and poor resolution of the usual prior art masters are overcome.

Moreover, unlike many prior art electronic and/or electrostatographic printing processes using conventional photoreceptors, such as conventional laser xerography, where the imagewise exposure step must be repeated for each print, the imagewise exposure process must be repeated for each print. The process only needs to be carried out once to produce the electrostatic printing master of the present invention, and a large number of prints can be produced from this master at high speed.

That is, the electrostatic printing system of the present invention overcomes the fundamental electronic bandwidth problems that have hindered conventional electrostatographic attempts at extremely high quality, high speed electronic black and white or color printing. That is, the combined ability of high photosensitivity, high quality and high printing speed at a reasonable cost makes the electrostatic printing master and electrostatic printing apparatus of the present invention suitable for high quality color proofing and printing/copying applications. It is intended to be applicable to both.

When compared to offset printing, the electrostatic printing method of the present invention has low master costs (no separate lithographic intermediate and printing plate are required; in offset printing, the intermediate is sufficiently small to be directly imaged by the printing plate). (instead, the printing plate is contact-exposed to the intermediate using intense UV light and then chemically developed), a simple fabrication process with no effluent, improved printing With the advantages of stability, and substantially reduced time and cost, the first receptacle provides a printable print. As a result, this necessitates the use of entirely different printing techniques for color proofing and color printing as required by prior art methods (and requires the end user to use Therefore, the electrostatic printing master and electrostatic printing method of the present invention is not only practical but also less costly than other known methods. By dividing into various layers, the imaging member of the present invention provides maximum flexibility in the selection of appropriate materials to maximize its mechanical, chemical, imaging and electrostatic printing properties. The electrostatic printing master of the present invention is formed by a permanent structural change of the migration marking material without removing or discarding any components from the softenable layer.In other words, the specific image is Due to the formation characteristics, the electrostatic printing master and electrostatic printing method of the present invention have a simple preparation method, low cost, high photosensitivity, easy master preparation method without effluent, high quality, high resolution and high printing speed. has many advantages.

Applications of this electrostatic printing system therefore include various types of printing systems such as high quality color printing and color proofing. Moreover, because of its high photosensitivity and charge transport ability, the master precursor material for electrostatic printing of the present invention can easily be used as a normal photoreceptor in normal electrostatic copying. Furthermore, since the visible image on the electrostatic printing master has a high optical contrast density, the electrostatic printing master of the present invention can be used in place of the conventional silver halide film used as an intermediate film. In addition to being used as a master for electrostatic printing, it can also be used to create regular printing plates for off-grid printing.

EXAMPLES The invention will now be described in detail with reference to certain preferred embodiments, but these examples are intended to be illustrative only and are not intended to define the scope of the invention. Please note. Parts and percentages are by weight unless otherwise indicated.

Example 1 A master precursor material for electrostatic printing similar to that illustrated in FIG.
80/0% by weight of styrene-hexyl methacrylate
20 mol% copolymer, and about 4.8% by weight N, N
'-Diphenyl-N,N'-bis(3"-methylphenyl)-(L,L'-biphenyl)-4,4'-diamine was prepared by dissolving approximately sO,2% toluene. The resulting solution was 12 inches (<30.5 cm) wide, with a thin translucent aluminum coating, using a 25 wire spout and throat.
．． cam (3 mil) jW mylar polyester film (E,!, available from DuPont).

The attached softenable layer was dried at about 110°C for about 15 minutes.

The thickness of the dry softenable layer was approximately 5 microns.

The temperature of the softenable layer was raised to about 115° C. and the exposed surface of the softenable layer had a viscosity of about 5×10 3 poise in preparation for the deposition of the marging material. A thin layer of granular vitreous selenium was then applied by vacuum evaporation in a vacuum chamber maintained at a vacuum of about 4xlO-'l-. The imaging member was then rapidly cooled to room temperature. A red monolayer of selenium particles with an average diameter of about 0.3 μm embedded about 0.05-0.1 μrn below the exposed surface of the copolymer was formed. Thereafter, the obtained master precursor material for electrostatic printing was positively corona-charged to a surface potential of approximately +400 volts, and a stair-knob wedge was formed.
by a combined steam-heat processing process comprising exposure to activating radiation of , imaged and developed.

The resulting imaged migration image forming section +A has an optically sign-inverted image of the original image, excellent image quality, a resolution of 228 line pairs/'@1 or more, and a relative density of about 0.67. Indicated. Dmax is approximately 0.95, Do,
7 was about 0.28. Also, transparent and extremely low D1
It was found that □□ is based on the aggregation and fusion of small amounts of selenium particles into larger particles in the D s + n nM region of the image. Next, the above electrostatic printing master was charged with a positive corona charge to approx. It was uniformly charged to +600 volts and then uniformly flash exposed per knot to 440 t+m of activating radiation at approximately 10 ergs/-. The surface potential is D m m m of the image
+50 volts in the eM region and about +400 volts in the D,.7 region, thereby obtaining an electrostatic contrast potential of about 1350 volts. The resulting electrostatic latent image was toned with negatively charged toner particles comprising a carbon blank pigmented styrene/butyl methacrylate-1 resin having an average particle size of about 10 micrometers. The adhered toner image was electrostatically transferred to a paper sheet by corona charging the back side of the paper, and the transferred toner image was then heat fused to obtain a high quality print. The transfer print has a contrast density of approximately 1.1 and a
It had a resolution of 5 line pairs/■1 or more.

Example 2 A master precursor material for electrostatic printing similar to that illustrated in FIG. A thin adhesive layer was prepared by hand coating onto aluminized polyester having a thickness of about 76 μm (3 mils). The adhesive layer had a thickness of about 011 μm when dried at 110° C. for 5 minutes. Thereafter, a charge transport spacing layer is formed with about 20% by weight polycarbonate resin and about 6% by weight N,N'-diphenyl-N,N'-based on the total weight of the resulting solution.
It was formed on the adhesive layer by dissolving bis(3"-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine in about 74% by weight methylene chloride solvent. 110°C. After drying for about 15 minutes at , the charge transport spacing layer had a thickness of about 4 pm.The imaging softenable layer was then applied over the charge transport spacing layer at a thickness of about 1
5% by weight of 80/20 mol% styrene-hexyl methacrylate copolymer and 3% by weight of N,N'-diphenyl-N,N'-bis(3"-methylphenyl)-(1,1
'-biphenyl)-4,4'-diamine in approximately 82% by weight toluene (all mixing proportions are based on the total weight of the solution). After drying at 110° C. for about 15 minutes, the imageable softenable layer was about 2 μm. The temperature of the softening layer is about 11
Raise the temperature to 5℃ to increase the viscosity of the exposed surface of the softenable layer to about 5XIO3
This was used as a void to prepare for the attachment of marking material.

A thin layer of granular vitreous selenium is then applied to approximately 4 x 10-'
It was applied by vacuum evaporation in a vacuum chamber maintained at a vacuum of 1. The imaging member was then rapidly cooled to room temperature. Approximately 0.0 below the exposed surface of the copolymer
A red monolayer of selenium particles with an average diameter of about 0.3 μm embedded in 5-0.1 μm was formed.

An electrostatic printing master was then prepared in the same manner as described in Example 1 using this electrostatic printing master precursor material. Background density of approximately 0.30 and 228
An optically sign-reversed visible image with a resolution of line pairs/1 m or more was obtained. Next, add this electrostatic printing master to approximately +7
Charged to a potential of 0.00 volts by positive corona charging to approximately 8.0 volts.
A uniform flash exposure was made to 400-700 nm white light at 0 ergs/ctA. The surface potential in the D TmaX region of the image was approximately +40 volts, and the surface potential in the D1□7 region was +400 volts, giving a contrast potential of approximately +360 volts. The obtained electrostatic latent image was
The toner was toned with negatively charged toner particles containing a carbon blank pigmented styrene/butyl methacrylate resin having m. The adhered toner image was electrostatically transferred to a paper sheet by corona charging the back side of the paper, and the transferred toner image was then heat fused to obtain a high quality print.

The transfer print has a contrast density of approximately 1.1 and 15 line pairs/mn
It had a higher resolving power.

Example 3 An electrostatic printing master precursor material similar to that illustrated in FIG. The transfer spacing layer was made of about 20% by weight styrene ethyl acrylate acrylic acid resin (RP1215, available from Monsanto) and about 6.8% by weight N,N'-diphenyl-N, based on the total weight of the resulting solution. , N'-bis(3"-methylphenyl)-
(1,1"-biphenyl)-4,4'-diamine about 7
It was prepared by dissolving in 3.2% by weight toluene and coating the resulting solution.

After drying at 110'C for about 15 minutes, the charge transport spacing layer had a thickness of about 6 μm. An imaging softening layer is then applied to the charge transport spacing layer with about 15% by weight of 80/20 mole % styrene-ethyl acrylate copolymer and 2.4% by weight N.

N'-diphenyl-N,N'-bis(3#-methylphenyl)-(1,1'-biphenyl)-4゜4'-diamine in about 50% by weight cyclohexane solvent and about 32% by weight toluene. (all mixing proportions are based on the total weight of the solution).

After drying at 110° C. for about 15 minutes, the imageable softenable layer has a thickness of about 2
It was μm. The temperature of the softenable layer was raised to about 115 DEG C. and the exposed surface of the softenable layer had a viscosity of about 5.times.10'3 poise in preparation for the deposition of the marking material. A thin layer of granular vitreous selenium was then applied by vacuum deposition in a vacuum chamber maintained at a vacuum of approximately 4×10 −' Torr.

The imaging member was then rapidly cooled to room temperature. A red monolayer of selenium particles with an average diameter of about 0.3 μm embedded about 0.05-0.1 μm below the exposed surface of the copolymer was formed.

An electrostatic printing master was then prepared in the same manner as described in Example 1 using this electrostatic printing master precursor material. Background density of approximately 0.25 and 228
An optical sign-reversed visible image with a resolution superior to that of line pairs/fins was obtained. This static reprint tdl master was pulsed by positive corona charging to a potential of 850 hol 1-) and uniformly exposed to 440 nm activating radiation of about IO erg/CffI.

Statue glue. i*if [the surface potential in the area is approximately +85 volts, ■)9. The surface potential of the area was 575 volts, giving a contrast potential of about +-490 volts. The resulting electrostatic latent image was toned with D, charged toner particles containing a carbon black pigmented styrene/butadiene resin having an average particle size of 6 .mu.m to form a 1-toner image. The toner image was electrostatically transferred to the paper sheet by corona charging the back side of the paper, and the transferred toner image was then fused to a high quality print. The transfer print has a contrast density of approximately 1.3 and 15 line pairs/1
It had a resolution of more than m.

Example 4 First, a master precursor material for electrostatic printing similar to that exemplified in the figure was prepared using 'eJ
15.0 weight 95 styrene-hexyl methacrylate 80. /20 mol% copolymer and 1.8 wt% N,N'-diphenyl-N,N'-bis(3''-methylphenyl)-(1,1'-biphenyl)-4,4'
-Made by dissolving the diamine in about 80.2% by weight toluene. The resulting solution was blown into a 12 inch (30,5 cm) wide, 76 μm tube with a thin translucent aluminum coating using a 10 wire wound iron.
m (3 mil) thick mylar polyester film (E,
1. available from DuPont).

The attached softenable layer was dried at about 110'C for 15 minutes.

The dry softenable layer thickness was 712 microns. The temperature of the softenable layer was raised to about 115° C., and the viscosity of the exposed surface of the softenable layer was set to about 5XIO' voids to prepare a hole for adhesion of the marking material. A thin layer of granular glass n selenium was then applied by vacuum deposition in a vacuum chamber maintained at a vacuum of about 4XlO-'l--. The imaging member was then allowed to cool to room temperature. Red monomolecules 1d of selenium particles with an average diameter of about 0.3/l m embedded about 0.05-0.1 μm below the exposed surface of the polymer 1'1. Ta. Thereafter, the obtained master precursor leaf material for electrostatic printing was charged to a surface potential of +200 volts by +210 volts, exposed to activation radiation using a step wedge, and methylated in a steam chamber. 1. Exposure to Ezirketone for 20 seconds.
Approximately 11 times on the 1-plate in contact with 1 ester
Images were formed and developed by a combined steam-heat processing process, each step of which involved heating to 5° C. for about 3 seconds.

The imaged migration imaging member exhibited an optically sign-reversed image of the original image, excellent image quality, a resolution of greater than 228 line pairs/mm, and a relative rt density of about 0.65. D, □ was about 0.95, and D, ... was about 0.3. It was also found that the very low Dl,1 of the transparency is due to the agglomeration and fusion of selenium particles into fewer and larger particles in the D*in region of the image.

The electrostatic printing master described above was then uniformly charged to about +250 volts with a positive corona charge and then uniformly flash exposed to 440 nm activating radiation of about 10 ergs/cIA. The surface potential is above 22 volts in the D□-n region of the image, D II i. Approximately +93 within the area
volts, thereby giving an electrostatic contrast potential of approximately +71 volts. The obtained electrostatic latent image was
The deposited toner image was toned with negatively charged toner particles comprising a carboblack pigmented styrene/butadiene resin having m. The adhered toner image was electrostatically transferred to the paper sheet by corona charging the back side of the paper, and the transferred light image was then heat-fixed. The transferred image exhibited poor quality and low print density due to its relatively low electrostatic contrast potential (approximately 71 volts) of the electrostatic latent image when developed with dry toner.

Example 5 An electrostatic printing master precursor member similar to that illustrated in FIG. 80/20 mole% of styrene-hexyl methacrylate
The copolymer was made by dissolving it in about 85% by weight toluene.

The resulting solution was prepared using a Nt125' twist-wound lot with a thin translucent aluminum coating.
2 inch (30,5 cm) wide, 76 μm (3 mil) thick Mylar polyester film (E, I).

available from DuPont). The attached softenable layer was dried at about 110°C for about 15 minutes. The thickness of the dry softenable layer was approximately 5 microns. The temperature of the softening layer is about 1
The viscosity of the exposed surface of the softenable layer was increased to approximately 5×10 by increasing the temperature to 15°C.
3 voids was set to 'JA6m' for the attachment of the marking material. A thin layer of granular vitreous selenium is then applied to approximately 4X10
It was applied by vacuum evaporation in a vacuum jumper maintained at a vacuum of -'l--. The imaging member was then rapidly cooled to room temperature. Approximately 0 below the exposed surface of the copolymer
, average diameter of about 0.3μ embedded in 05-0.1μm
A red monolayer of selenium particles containing m was formed.

Thereafter, the obtained electrostatic printing master precursor member was positively corona charged to a surface potential of approximately +400 volts,
Imaged and developed by a heat processing process comprising exposure to activating radiation through a temp wedge and heating to about 115° C. for about 5 seconds on a hot plate in contact with the polyester. . It has been found that without charge transport molecules in the softenable layer, the sign-reversed image obtained exhibits a contrast density of only about 0.3. DmaX was about 0.60 and Dmin was about 0.3. Also, the low D-i was due to the substantially deep dispersion of the migrating selenium particles towards the substrate in the D□x pU region of the image and Dmin is the D a r of the image. It was found that the area was based on agglomeration and fusion of selenium particles.

The imaged member was then uniformly charged to about +550 volts by positive corona charging and flash-exposed uniformly and economically to about 10 ergs/ct of 440 nm activating radiation. The surface potential is D□, and D m i
No electrostatic images were obtained since both n regions were at approximately +520 volts.

Example 6 A master precursor material for electrostatic printing was prepared as in Example 3, containing about 10% by weight of a stylized acrylic copolymer (Neocryl A-1054 available from Polyvinyl Chemical Industries, Inc.) and about 0.03% by weight polysiloxane resin (Byk 301.13y
The sample was overcoated with an aqueous solution containing K-Marine Co., Ltd.). The dried overcoating had a thickness of approximately 1.5 μm. The resulting overcoated electrostatic printing master precursor piece was then positively corona charged to a surface potential of approximately +600 volts, exposed to activating radiation through a yin-yang wedge, and exposed to methyl ethyl ketone in a steam chamber. The images were imaged and developed by a combined steam-heat processing process comprising a 60 second exposure and heating to about 115 DEG C. for about 10 seconds on a hot plate in contact with the substrate polyester. The resulting imaged migration imaging member exhibited an optically sign-reversed image of the original image, excellent image quality, a resolution of greater than 228 line pairs per square inch, and a contrast density of about 1.2. D□ was approximately 1.48, and D m =n was approximately 0.28. The imaged member exhibited excellent abrasion resistance when scratched with a fingernail. This overcoated imaging member retained its integrity when subjected to extremely rigorous adhesive tape testing with Scotch brand "Magic" adhesive tape. It was also found that the very low D win of the transparency is based on the agglomeration and fusion of selenium particles into fewer and larger particles in the D m i h region of the image.

The electrostatic printing master described above was then uniformly charged to about +800 volts with a positive corona charge and then briefly uniformly flash exposed to 400-700 nm white light at about 100 ergs/cI11. The surface potential is the Dmawe of the image.
It was +120 volts in the M region and about +520 volts in the D m i region, thereby giving an electrostatic contrast potential of about +400 volts.

The resulting electrostatic latent image was toned with negatively charged toner particles comprising a carbon blank pigmented styrene/butyl methacrylate resin having an average particle size of about 6 micrometers to form a deposited toner image. Adhesion] - The toner image was electrostatically transferred to a paper sheet by corona charging the back side of the paper, and the transferred toner image was then heated and fixed to obtain a high-quality print.3 The transfer print was approximately It had a contrast density of 1.3 and a resolution of more than 15 line pairs/1 line.

Example 7 A master precursor material for electrostatic printing similar to that illustrated in FIG.
0% by weight styrene-ethyl acrylate-acrylic acid terpolymer and about 2.4% by weight N,N'-
diphenyl-N,N'-bis(3#-methylphenyl1
It was made by dissolving -(1,1'-biphenyl)-4,4'-diamine in about 82.6% by weight toluene.

The obtained solution was mixed with a 25 wire winding iron.
12 inch (30,5 CIm) wide, 76, urn (3 mil) thick Mylar polyester film (E, I) with a thin translucent aluminum coating.

(available from Devon). The attached softenable layer was dried at about 110°C for about 15 minutes. The thickness of the dry softenable layer was approximately 4.0 microns. The temperature of the softening layer was raised to 115°C to reduce the viscosity of the exposed surface of the softening layer to about 5.
i4i of marking material adhesion as x103poise
It was set to 6M. A thin layer of granular vitreous selenium was then applied by vacuum deposition in a vacuum chamber maintained at a vacuum of approximately 4×10 −' Torr. The imaging member was then rapidly cooled to room temperature. An average diameter of about 0 embedded approximately 0.05-0.1 μm below the exposed surface of the copolymer.
．． A red monolayer of selenium particles with a diameter of 3 μm was formed. The resulting electrostatic printing master precursor part was then positively corona charged to a surface potential of approximately +20 volts, exposed to activating radiation through a yin-yang wedge, and immersed in methyl ethyl cane in a steam chamber to approximately +20 volts. Imaged and developed by a combined steam-heat processing process comprising a 35 second exposure and heating to about 115'C for about 5 seconds on a hot plate in contact with the polyester.

The resulting imaged migration imaging member is
It exhibited an optically sign-reversed image of the original image, excellent image quality, a resolution of better than 228 line pairs per dragon, and a contrast density of about 0.9. D, □ is approximately 1.2, and D a = , 1 is approximately 0.
It was 3. Also, the transparent extremely low diameter of 1.7 is the D of the image.
m i was found to be based on the agglomeration and fusion of selenium particles in the region into fewer and larger particles.

The electrostatic printing master described above was then uniformly charged to about +500 volts with a positive corona charge and then briefly uniformly flash exposed to 400-700 nI11 activation radiation at about 40 ergs/cd. The surface potential is D of the image
+70 volts in the saw region and D m i. approximately +25 volts within the region, thereby obtaining a static contrast potential of approximately +250 volts.

The resulting electrostatic latent image was toned with negatively charged liquid toner particles comprising carbon blank pigmented polyethylene/acrylic acid resin having an average particle size of 1 about 0.2 μm to form a deposited toner. The adhered toner image was electrostatically transferred to the paper sheet by corona charging the back side of the paper, and the transferred toner image was then heat-fixed to obtain a high quality print.

The transfer print had a contrast density of approximately 1.9 and a resolution of greater than 60 line pairs/■■.

Example 8 An electrostatic printing master member similar to the member of Example 3 was produced. The electrostatic printing master was uniformly charged to about +700 volts with a positive corona charge and then flashed briefly and uniformly to 400-700 nm white light at about 100 ergs/ctA. The surface potential is D+aix of the image
It is +50 volts in the lI region and about + in the Dl,7 region.
450 volts, thereby giving an electrostatic contrast potential of approximately +400 volts.

The electrostatic latent image is then scanned at 400-700 nm and approximately 100 nm.
It was erased by uniform and intense irradiation with white light at 0 erg/crA. The above uniform charging, uniform exposure and erasure are carried out in 1
Repeated 000 times. This electrostatic printing master part is stable and has +50 volts in the DnixeU area of the image and Dain? It was found that the cycle-to-cycle surface potential of about 450 volts in the 'ff region remained essentially unchanged.

Example 9 An electrostatic printing master member similar to the member of Example 3 was produced. This electrostatic master was pasted onto a bare drum to replace the original photoreceptor drum in an automatic copier. This electrostatic printing master was uniformly charged to about +700 volts with a positive corona charge, uniformly exposed to flash radiation to form an electrostatic latent image, which was then transferred to carbon black colored styrene having an average grain size of about 6 μm. Toner was applied with negatively charged toner particles containing /butadiene resin to form a deposited toner image. The adhered toner image was electrostatically transferred to a paper sheet by corona charging the backside of the paper, and then the transferred toner image was heat-fixed to obtain a high quality print. This electrostatic printing process was repeated at least 150 times with very good results.

Other variations of the invention will be apparent to those skilled in the art from this description. Thus, for example, a second charging step that reduces the surface voltage to near zero may be used before the vapor exposure step.

This second charging step has a polarity opposite to that of the first charging. These modifications are considered to be within the scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of one embodiment of a master precursor member for multilayer electrostatic printing. FIG. 2 is a partial cross-sectional view of another embodiment of a master precursor member for multilayer electrostatic printing. FIG. 3 is a partial cross-sectional view of yet another embodiment of a master precursor member for multilayer electrostatic printing. FIG. 4 is a partial cross-sectional view of a typical electrostatic printing master. FIG. 5 is a partial cross-sectional view of a conventional electrostatic printing master in the process of receiving electrostatic charges. FIG. 6 is a partial cross-sectional view of a typical electrostatic printing master during development. FIG. 7 is a partial sectional view of a conventional electrostatic printing master in which a toner image is transferred to a receiving member. FIG. 8 is a partial cross-sectional view of a conventional electrostatic printing master during reception of electrostatic charge, showing the effect of a fringe electric field. FIG. 9 is a partial cross-sectional view of a master precursor member for electrostatic printing of the present invention while receiving an electrostatic charge. FIG. 10 is a partial cross-sectional view of a master precursor member for electrostatic printing of the present invention during exposure to image-shaped activation electromagnetic radiation. FIG. 11 is a partial cross-sectional view of an electrostatic printing master precursor member of the present invention during exposure to solvent vapor. FIG. 12 is a partial cross-sectional view of an electrostatic printing master precursor member of the present invention during exposure to heat. FIG. 13 is a partial sectional view of the electrostatic printing master of the present invention while receiving electrostatic charges. FIG. 14 is a partial cross-sectional view of the electrostatic printing master of the present invention being uniformly exposed to activating electromagnetic radiation. FIG. 15 is a partial cross-sectional view of the electrostatic printing master of the present invention during development. FIG. 16 is a partial sectional view of the electrostatic printing master of the present invention during transfer of a toner image to a receiving member. FIG. 17 is a partial cross-sectional view of the electrostatic printing master of the present invention during exposure to intense erasing electromagnetic radiation. 10... Master precursor member for electrostatic printing, 12
... Substrate, 14... Conductive layer, 16... Charge transport spacing layer, 18... Softenable Ji, 20... Migration marking material, 22... Adhesive layer, 2
4... Image forming master, 26... Electric conductor, 28...
- Insulating material, 30... Insulating image forming area, 32... Conductive non-image forming area, 38.40... Adhering toner image, 4
2... Receiving sheet, 44... Corotron, 46
...Acquired ion, 52...Conductive substrate, 54...
Charge transport layer, 56... Soft layer, 58... Migration marking material, 60... Corona charging device,
62...Irradiation for activation, 64...Solvent vapor, 66.
...Heating radiation. 1 to I N Engraving of the drawings (no changes to the contents) FIG, 8 Procedural amendment (method) 1. Display of case: 1988 Patent Application No. 332755
No. 2, Title of the invention Image forming device 3, Mi
Relationship with the person who makes the corrections: Applicant name: Xerox Corporation 4, agent

Claims (1)

[Claims] 1. An electrically insulating substrate having an intermediate layer selected from the group consisting of an adhesive layer, a charge transport spacing layer, and a combination layer of the adhesive layer and the charge transport spacing layer; and an imaging surface overlying the intermediate layer. the electrically insulating layer comprises a charge transport molecule and a closely spaced electrically photosensitive migration layer present at or near the imaging surface of the electrically insulating layer; a destructible layer of marking particles; said charge transport molecules capable of increasing charge injection from said electrically photosensitive migration marking material into said electrically insulating layer and transferring charge to a substrate; and further dissolved or molecularly dispersed in the electrically insulating softenable layer and the charge transport spacing layer.